Methods of suppressing LTP inhibition

ABSTRACT

Methods and compositions for suppressing amyloid-mediated inhibition of long-term potentiation (LTP) are provided.

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/190,548, filed Jul. 9, 2002, which claims the benefit ofpriority from U.S. Provisional Application No. 60/304,315, filed Jul. 9,2001, and U.S. Provisional Application No. 60/341,772, filed Dec. 17,2001. Those applications are hereby incorporated herein by reference intheir entirety.

Amyloidogenic proteins are involved in the pathology of multiple diseasestates. Diseases resulting from abnormal deposition of amyloidogenicproteins include, but are not limited to, Alzheimer's disease, type IIdiabetes, Parkinson's disease, diffuse lewy body disease, diseasescaused all or in part by prions (such as Creutzfeldt-Jakob disease,scrapie, and bovine spongiform encephalopathy), and amyloidoses,including both hereditary amyloidoses and systemic amyloidoses.

Alzheimer's disease (AD) is a progressive neurodegenerative diseaseresulting in senile dementia that afflicts four million people in theUnited States alone (see generally Sloe, TINS, 16:403-409 (1993); Hardyet al., WO 92/13069; Sloe, J. Neuropathol. Exp. Neurol., 53:438-447(1994); Duff et al., Nature, 373:476-477 (1995); Games et al., Nature,373:523 (1995). Broadly speaking, the disease falls into two categories:late onset, which occurs in old age (65+ years); and early onset, whichdevelops well before the senile period, i.e., between 35 and 60 years.In both types of disease, the pathology is the same but theabnormalities tend to be more severe and widespread in cases beginningat an earlier age. The disease is characterized by at least two types oflesions in the brain, senile plaques and neurofibrillary tangles.Neurofibrillary tangles are intracellular deposits of microtubuleassociated tau protein consisting of two filaments twisted about eachother in pairs. Senile plaques are areas of disorganized neuropil up to150 microns across (visible by microscopic analysis of sections of braintissue) and have extracellular amyloid deposits at the center. Theprincipal component of such plaques is Aβ peptide (see Forsyth Phys.Ther., 78:1325-1331 (1998)). Additional proteins found in the plaquesinclude laminin as described by Murtomaki et al., J. Neurosci. Res.,32:261-273 (1992), apoE, acetylcholinesterase, and heparin sulfateproteoglycans, as described by Yan et al., Biochim. Biophys. Acta,1502:145-57 (2000). Aβ peptide is an internal fragment of 39-43 aminoacids of a precursor protein termed amyloid precursor protein (APP).Several mutations within the APP protein have been correlated with thepresence of Alzheimer's disease (Goate et al., Nature, 349:704-06 (1991)(valine⁷¹⁷ to isoleucine); Harlin et al., Nature, 353:844-46 (1991)(valine⁷¹⁷ to glycine); Murrell et al., Science, 254:97-99 (1991)(valine⁷¹⁷ to phenylalanine); Mullan et al., Nature Genet., 1:345-47(1992) (a double mutation changing lysine⁵⁹⁵methionine⁵⁹⁶ toasparagine⁵⁹⁵leucine⁵⁹⁶). Such mutations are thought to causeAlzheimer's disease by increased or altered processing of APP to Aβ,particularly processing of APP to increased amounts of the long form ofAβ (i.e., A1-42 and A1-43). Mutations in other genes, such as thepresenilin genes PS1 and PS2, are thought to indirectly affectprocessing of APP to generate increased amounts of long form Aβ (Hardy,TINS, 20:154 (1997)). These observations indicate that Aβ, andparticularly its long form, is a causative element in Alzheimer'sdisease (Velez-Pardo et al., Gen. Pharm., 31(5):675-81 (1998)).

Researchers postulate that synaptic failure underlies the onset of AD,as synaptic loss is an early event in AD and is a structural correlateof cognitive dysfunction. Researchers further postulate that the mildcognitive impairment that precedes the insidious onset of clinicaldementia in AD results from synaptic dysfunction preceding large scaleneurodegeneration. Long-term potentiation (LTP) is a form of synapticplasticity that has been widely hypothesized to be a cellular model oflearning and memory.

LTP is a persistent, use-dependent increase in the efficiency ofsynaptic transmission. In most investigations, LTP is experimentallyinduced by the delivery of high-frequency synaptic stimulation (HFS).However, other conditioning protocols exist, some of which arepharmacological in nature and do not involve synaptic stimulation.Furthermore, multiple forms of LTP have been identified. Studies inrodent brain slices have illucidated many aspects of LTP, particularlyat the CA3-CA1 synapse of the hippocampus. Four features of LTP arecooperativity, associativity, persistence, and input-specificity.

The process of LTP induction, which constitutes those early events thatinitiate the increase in synaptic efficiency, is mechanisticallydistinct from the subsequent, persistent expression of LTP. During LTPinduction, the delivery of HFS to fibers that project from area CA3 toarea CA1 releases glutamate into the synapse and depolarizes thepostsynaptic neuron. Due to the high frequency of stimulation (forexample 100 Hz), the depolarizations induced by successive excitatorypostsynaptic potentials (EPSPs) overlap, and the cumulativedepolarization during a train of HFS can be substantial. The generationof postsynaptic action potentials that back-propagate to the dendritescontribute additional depolarization. Although the glutamate release andthe depolarization are causally related, experimentally it is possibleto separate them and demonstrate that the induction of LTP requires bothevents, a relationship that has been termed “cooperativity.” Thus, HFSfails to induce LTP if the postsynaptic membrane is directlyhyperpolarized during conditioning. Conversely, directly depolarizingthe postsynaptic membrane with current injection enables evenlow-frequency synaptic stimulation to induce LTP.

Almost all individuals with Down's syndrome, who have an extra copy ofchromosome 21, show neuropathological changes similar to those seen inAlzheimer's disease, if they survive into their 40s. This has beenattributed to excess production of beta-amyloid protein, which isencoded by the APP gene on chromosome 21.

Several proteins have been investigated for possible interactions withAβ. These include the receptor for advanced glycation endproducts, RAGE(see Yan et al., Nature, 382:685-91 (1996)), the scavenger receptor(Khoury et al., Nature, 382:716-719 (1996); and Paresce et al., Neuron17:553-65 (1996)), the endoplasmic reticulum-associated amyloid-betabiding protein (ERAB) (Yan et al., Nature, 389:689-695 (1997)), α4 or α7nicotinic acetylcholine receptor (Wang et al., J. Neurochem.,75:1155-1161 (2000) and Wang et al., J. Biol. Chem., 275:5626-5632(2000)), and the low affinity p75 NGF receptor (see Yaar et al., J.Clin. Invest., 100:2333-2340 (1997)). Additionally, Aβ has been reportedto mediate adhesion of cells in a β1-integrin subunit dependent mannerwhen coated onto plates by Ghiso et al., Biochem. J, 288:1053-59 (1992);and Matter et al., J. Cell Bio., 141:1019-1030 (1998).

In view of the number of different molecules of various functions thatmay interact with Aβ, the mechanism by which Aβ may mediateneurodegeneration remains unclear. The existence and nature of othercellular proteins that may have roles in the process is also unclear.

Islet amyloid has been recognized as a pathological entity in type IIdiabetes since the turn of the century. It has as its unique componentthe islet β-cell peptide, islet amyloid polypeptide (IAPP) or amylin,which is co-secreted with insulin. In addition to this unique component,islet amyloid contains other proteins, such as apolipoprotein E and theheparin sulfate proteoglycan perlecan, which are typically observed inother forms of generalized and localized amyloid. Islet amyloid isobserved at pathological examination in the vast majority of individualswith type II diabetes but is rarely observed in humans withoutdisturbances of glucose metabolism. In contrast to IAPP from rodents,human IAPP has been shown to form amyloid fibrils in vitro. Because allhuman subjects produce and secrete the amyloidogenic form of IAPP, yetnot all develop islet amyloid, some other factors are likely to beinvolved in islet amyloid formation. One hypothesis is that analteration in β-cell function resulting in a change in the production,processing, and/or secretion of IAPP is involved in the initialformation of islet amyloid fibrils in human diabetes. This formation ofamyloid fibrils then allows the progressive accumulation ofIAPP-containing fibrils. The eventual replacement of β-cell mass byamyloid contributes to the development of hyperglycemia.

One factor that may be involved in producing the changes in the β-cellthat result in the initiation of amyloid formation is the increasedconsumption of dietary fat. Dietary fat is known to alter islet β-cellpeptide production, processing, and secretion, and studies in transgenicmice expressing human IAPP support the operation of this mechanism.Further investigation using this and other models should provide insightinto the mechanisms involved in islet amyloidogenesis and allow thedevelopment of therapeutic agents that inhibit or reverse amyloid fibrilformation, with the goal being to preserve β-cell function and improveglucose control in type II diabetes. Diabetes, 48:241-253 (1999).

The transmissible spongiform encephalopathies, or prion diseases,constitute a group of transmissible, rapidly progressive, invariablyfatal neurodegenerative diseases that can manifest as acquired,hereditary or idiopathic (“sporadic”) diseases. They includeCreutzfeldt-Jakob disease in humans, as well as scrapie and bovinespongiform encephalopathy (BSE) in animals, and are characterized by along incubation period that may last up to decades after experimental oraccidental transmission. The classic pathological features of priondiseases include spongiform change, gliosis, and neuronal loss. Incontrast to what is typically seen in infectious diseases caused byviruses, prion diseases lack a significant inflammatory response(Prusiner, Arch. Neurol., 50:1129-1153 (1953), Prusiner, Proc. Natl.Acad. Sci. U.S.A., 95:13363-13383 (1998).

Prion diseases have received considerable scientific attention due tothe unique properties of the transmissible agent, the “prion” (Prusiner,Science, 216:136-144 (1982)). The infectious agent is very small andextremely resistant to treatments that destroy nucleic acids andinactivate conventional viruses (id.), but is susceptible to treatmentsthat denature proteins. Attempts to purify the infectious agent yieldedfractions highly enriched for a hitherto unknown protein, which has beennamed prion protein (PrP) (Bolton et al., Science, 218:1309-1311 (1982);Prusiner et al., Cell, 38:127-134 (1983); Oesch et al., Cell, 40:735-746(1985)). No agent-specific nucleic acid has been found in thesepreparations (Kellings et al., J. Gen. Virol., 73:1025-1029 (1992);Riesner et al., Dev. Biol. Stand., 80:173-181 (1993)); rather, the prionprotein is encoded in the host genome (Oesch et al., Cell, 40:735-746(1985); Chesebro et al., Nature, 315:331-333 (1985); Basler et al.,Cell, 46:417-428 (1986)). In the brains of affected individuals, apathognomonic accumulation of a specific disease-associated isoform ofthe prion protein, termed PrP^(Sc), is found (FIG. 1). PrP^(Sc) isderived through an ill-defined post-translational process involvingconformational changes from the normal cellular isoform of the prionprotein (PrP^(C)) (Prusiner, Proc. Natl. Acad. Sci. U.S.A.,95:13363-13383 (1998)). PrP^(C) and PrP^(Sc) have the same amino acidsequence (Stahl et al., Biochemistry, 32:1991-2002 (1993)), however,they differ in conformation. PrP^(Sc) can be distinguished from PrP^(C)by its high content of β-sheet structures (Pan et al., Proc. Natl. Acad.Sci. U.S.A., 90:10962-10966 (1993)), its tendency to form largeaggregates, and its partial resistance to digestion with proteinase K.

Hereditary amyloidoses comprise a clinically and geneticallyheterogeneous group of autosomal dominant inherited diseasescharacterized by the deposit of insoluble protein fibrils in theextracellular matrix. These diseases typically present symptoms ofpolyneuropathy, carpal tunnel syndrome, autonomic insufficiency,cardiomyopathy, and gastrointestinal features, occasionally accompaniedby vitreous opacities and renal insufficiency. Other phenotypes arecharacterized by nephropathy, gastric ulcers, cranial nerve dysfunction,and corneal lattice dystrophy. Rarely, the leptomeningeal or cerebralstructures are also involved in the clinical picture. The age at onsetis as early as 17 and as late as 78 years. The basic constituents ofamyloid fibrils are physiologic proteins that have become amyloidogenicthrough genetically determined conformation changes. Mutatedtransthyretin (TTR), formerly termed prealbumin, is the most frequentoffender in hereditary amyloidosis. Orthotopic liver transplantation(OLT) stops the progression of the disease, which is otherwise generallyfatal, by removing the main production site of the amyloidogenicprotein. The indications for OLT and its success depend on the grade ofcardiovascular and autonomic dysfunction at the time of surgery, age,comorbidity, and type of mutation. Alternative treatment modalities withdrugs stabilizing the native tetrameric conformation of TTR andinhibiting fibril formation are currently being intensively studied.

Systemic amyloidoses are characterized by the extracellular deposit offibrillary protein aggregations in parenchymal organs; blood vessels;subcutaneous, submucosal, and peritendinous fat; heart; eyes; andmeninges. In addition, any part of the peripheral nervous system may beinvolved, including the nerve trunks, plexuses, and the sensory andautonomic ganglia. In the peripheral nerves, amyloid deposits occur inthe epi-, peri-, or endoneurium, usually in a patchy and localizeddistribution. On light microscopy with conventional stains, amyloiddeposits have a homogeneous, eosinophilic appearance. With Congo redstaining, they show a characteristic yellow-green birefringence underpolarized light.

A variety of proteins are responsible for amyloid formation; in fact, atotal of 18 amyloidogenic proteins have been identified in humanamyloidoses. Nonhereditary systemic amyloidoses can be caused byimmunoglobulin light chains (AL-type, in plasma cell dyscrasias),fragments of serum amyloid A, an acute-phase protein (AA-type, inchronic inflammatory diseases), transthyretin (TTR; in senile systemicamyloidosis), and β₂-microglobulin (in patients with uremia anddialysis). Hereditary amyloidoses are due to genetic variants ofphysiologic proteins, including TTR and, much more rarely,apolipoprotein-A1, lysozyme, fibrinogen, gelsolin, amyloid-β, andcystatin C. TTR, formerly called prealbumin, is a normal tetramericserum protein that is involved in the transport of serum thyroxine andretinal-binding protein. It is encoded by a single gene on chromosome18, of which more than 70 autosomal dominantly inherited point mutationsoccurring at 51 different sites have been described. Among these,substitution of valine by methionine at position 30 (Met30) is by farthe most frequent and geographically most widely disseminated.

Parkinson's disease is a progressive neurological disorder marked bytremors, muscle rigidity, and balance and coordination problems. Thedestruction of brain cells that produce the chemical dopamine underliesthese symptoms. These diseased cells are also marked by protein depositscalled Lewy bodies. No one knows why the cells die or whether the Lewybodies help kill them. Mutations in the genes for two proteins, calledparkin and α-synuclein, are linked to separate, rare forms of inheritedParkinson's disease. But both parkin and α-synuclein are found in Lewybodies that build up in the brains of all Parkinson's disease patients.

Recent findings suggest that parkin plays an important role inregulating proteins associated with Lewy bodies in the brain, includingα-synuclein and synphilin. Normally, parkin uses yet another protein,called ubiquitin, to “tag” other proteins for destruction. But ifsomething goes wrong in the relationship among these proteins, thiscould lay the groundwork for the cell death seen in Parkinson's disease.Both parkin and α-synuclein are linked with synphilin-1 in a commonpathogenic mechanism involving the ubiquitination of Lewybody-associated proteins. Dawson et al., Nature Medicine, 7:1144-1150(2001). Thus, given its interaction with parkin, problems withα-synuclein may be at the core of both the inherited and common forms ofParkinson's disease. Id.

SUMMARY

Provided is a method of suppressing amyloid-mediated inhibition oflong-term potentiation (LTP), comprising administering an effectivedosage of one or more agents that bind to integrin subunit αv underconditions such that the one or more agents suppress amyloid-mediatedinhibition of LTP. In an embodiment of the method, effective dosages ofat least two agents that bind to integrin subunit αv are administered.In an embodiment of the method, the agent is administered in combinationwith a secondary agent chosen from the group consisting of an inhibitorof Aβ production, an inhibitor of Aβ deposition, a mediator of Aβclearance, a mediator of amyloid plaque clearance, an inhibitor of Aβneurotoxicity, an inhibitor of Aβ aggregation, and a mediator of Aβdisaggregation. In an embodiment, the inhibitor of Aβ production is agamma secretase inhibitor. In an embodiment, the inhibitor of Aβproduction is a beta secretase inhibitor. In an embodiment of themethod, the agent is administered in combination with an antibody to Aβ.In an embodiment of the method, the agent is a peptide comprising an RGD(Arg-Gly-Asp) motif. In an embodiment of the method, the agent is aligand of αvβ1 integrin. In an embodiment of the method, the agent isfibronectin or superfibronectin. In an embodiment of the method, theagent inhibits adhesion of αv integrin subunit-expressing cells tovitronectin or fibronectin. In an embodiment of the method, the agentinhibits adhesion of αv integrin subunit-expressing cells toosteopontin. In an embodiment of the method, the agent is a monoclonalor polyclonal antibody. In an embodiment of the method, the agent is anantibody that recognizes the same epitope as an antibody selected from18C7, 20A9, and 17E6. In an embodiment, the antibody is selected from ahumanized antibody, a chimeric antibody, and a nanobody. In anembodiment of the method, the agent is an antibody selected from 18C7,20A9, and 17E6. In an embodiment of the method, the agent competes forbinding to the integrin subunit αv with an antibody chosen from 18C7,20A9, and 17E6.

In a further embodiment of the method the agent is a compound selectedfrom compounds of Formula Ia and Ib

including stereoisomeric forms thereof, or mixtures of stereoisomericforms thereof, or pharmaceutically acceptable salt forms thereof,wherein:

X₁ and X₃ are independently selected from nitrogen or carbon;

R¹ is selected from:

wherein the above heterocycles are optionally substituted with 0-2substituents selected from the group consisting of: NH₂, halogen, NO₂,CN, CF₃, C₁-C₄ alkoxy, C₁-C₆ alkyl, and C₃-C₇ cycloalkyl;U is selected from —(CH₂)_(n)—, —(CH₂)_(t)Q(CH₂)_(m)— and —C(═O)

(CH₂)_(n-1), wherein one of the methylene groups is optionallysubstituted with R⁷; Q is selected from 1,2-phenylene, 1,3-phenylene,2,3-pyridinylene, 3,4-pyridinylene, and 2,4-pyridinylene;

R⁶ is selected from: H, C₁-C₄ alkyl, and benzyl;R7 is selected from: C₁-C₆ alkyl, C₃-C₇ cycloalkyl,

C₄-C₁₁ cycloalkylalkyl, aryl, aryl(C₁-C₆ alkyl), heteroaryl, andheteroaryl(C₁-C₆ alkyl);

R¹⁰ is selected from: H, halogen, CO₂R¹⁷, CONR¹⁷R²⁰, C₁-C₆ alkylsubstituted with 0-1 R¹⁵ or 0-1 R²¹, C₁-C₄ alkoxy substituted with 0-1R²¹, C₃-C₇ cycloalkyl substituted with 0-1 R¹⁵ or 0-1 R²¹, C₄-C₁₁cycloalkylalkyl substituted with 0-1 R¹⁵ or 0-1 R²¹, and aryl(C₁-C₆alkyl)-substituted with 0-1 R¹⁵ or 0-2 R¹¹ or 0-1 R²¹;R¹¹ is selected from: H, halogen, CF₃, CN, NO₂, hydroxy, NR²R³, C₁-C₄alkyl substituted with 0-1 R²¹, C₁-C₄ alkoxy substituted with 0-1 R²¹,aryl substituted with 0-1 R²¹, aryl(C₁-C₆ alkyl)-substituted with 0-1R²¹, (C₁-C₄ alkoxy)carbonyl substituted with 0-1 R²¹, (C₁-C₄alkyl)carbonyl substituted with 0-1 R²¹, C₁-C₄ alkylsulfonyl substitutedwith 0-1 R²¹, and C₁-C₄ alky-laminosulfonyl substituted with 0-1 R²¹;

W is —C(═O)—N(R¹³)—; X is —CH(R¹⁴)—CH(R¹⁵)—;

R¹³ is selected from H and CH₃;R¹⁴ is selected from: H, C₁-C₁₀ alkyl, aryl, and heteroaryl, whereinsaid aryl or heteroaryl groups are optionally substituted with 0-3substituents selected from: C₁-C₄ alkyl, C₁-C₄ alkoxy, aryl, halo,cyano, amino, CF₃, and NO₂;R¹⁵ is selected from H and R¹⁶;

Y is —COR¹⁹;

R¹⁶ is selected from:

—NH(R²⁰)—C(═O)—R¹⁷,

—N(R²⁰)—C(═O)—R¹⁷,

—N(R²⁰)—C(═O)—NH—R¹⁷,

—N(R²⁰)SO₂—R¹⁷, and

—N(R²⁰)SO₂—N(R²⁰)R¹⁷,

R¹⁷ is selected from: C₁-C₁₀ alkyl, C₃-C₁₁ cycloalkyl, aryl(C₁-C₆alkyl)-, (C₁-C₆ alkyl)aryl, heteroaryl (C₁-C₆ alkyl)-, (C₁-C₆alkyl)heteroaryl, biaryl(C₁-C₆ alkyl)-, heteroaryl, or aryl, whereinsaid aryl or heteroaryl groups are optionally substituted with 0-3substituents selected from the group consisting of: C₁-C₄ alkyl, C₁-C₄alkoxy, aryl, heteroaryl, halo, cyano, amino, CF₃, and NO₂;

R¹⁹ is —O—(CH₂)_(k)N⁺(R²²)(R²³)(R²⁴)Z⁻;

Z⁻ is a pharmaceutically acceptable anion selected from halide,bisulfate, sulfate, hydrogenphosphate, phosphate, toluenesulfonate,methanesulfonate, ethanesulfonate, acetate, trifluoroacetate, citrate,oxalate, succinate, and malonate;

R²², R²³, and R²⁴ are independently selected from H, C₁-C₄ alkyl, andC₄-C₁₁ cycloalkylalkyl;

alternatively R²² and R²³ can be taken together to form a 5-7 memberedheterocyclic ring system containing 1-2 heteroatoms selected from N, Oand S, and R²⁴ is defined as above or R²², R²³, and R²⁴ can be takentogether to form a heterobicyclic ring system containing 1-2 heteroatomsselected from N, O and S;

R²⁰ is selected from H and CH₃;

R²¹ is selected from COOH and NR⁶ ₂;

k is 2;m is selected from 0 and 1;n is 1-4; andt is selected from 0 and 1.

In an embodiment of the method, the agent is a compound of Formula II:

wherein R¹⁹ is chosen from —H, —CH₃, and —CH₂CH₂N⁺(CH₃)₃. In anembodiment, R¹⁹ is —H. In another embodiment, R¹⁹ is —CH₃. In anotherembodiment, R19 is —CH₂CH₂N⁺(CH₃)₃.

In another embodiment of the method, the agent is a disintegrin. Inanother embodiment of the method, the agent is echistatin. In anotherembodiment of the method, the agent is a human antibody. In anotherembodiment of the method, the agent is a humanized antibody. In anotherembodiment of the method, the agent is a chimeric antibody. In anotherembodiment of the method, the agent is a nanobody. In another embodimentof the method, the agent is an antibody fragment. In another embodimentof the method, the agent comprises one or more heavy chains, lightchains, F(ab), F(ab)₂, F(ab)_(c), or F(v) of an antibody, or anycombination thereof. In another embodiment of the method, the agent isan antibody and the isotype of the antibody is IgG1 or IgG4. In anotherembodiment of the method, the agent is an antibody and the isotype ofthe antibody is IgG2 or IgG3. In another embodiment of the method, theagent is an antibody chain. In another embodiment of the method, theagent is an antibody and the antibody comprises two pairs of light andheavy chains.

In another embodiment of the method, the agent is administered to apatient. In an embodiment, the agent is an antibody and the dosage ofthe antibody ranges from about 0.01 to about 10 mg/kg body weight of thepatient. In an embodiment, the agent is administered with a carrier as apharmaceutical composition. In an embodiment, the agent is administeredintraperitoneally, orally, intranasally, subcutaneously, intrathecally,intramuscularly, topically or intravenously. In an embodiment, thepatient is suffering from an amyloidogenic disease. In an embodiment,the disease is chosen from the group consisting of Alzheimer's disease,type II diabetes, Parkinson's disease, diffuse lewy body disease,amyloidosis, Down's syndrome, and a disease caused all or in part byprion infection.

In another embodiment of the method, a nucleic acid is administered thatencodes the agent. In another embodiment of the method, the agent ischosen from the group consisting of an antisense RNA molecule, anantisense DNA molecule, a ribozyme, RNAi, and a zinc-finger protein. Inanother embodiment, the method further comprises inhibiting formation ofan amyloid deposit. In another embodiment, the method further comprisesinhibiting amyloid toxicity. In another embodiment of the method, theagent does not block the maintenance phase of LTP. In another embodimentof the method, the agent suppresses amyloid-mediated inhibition of LTPin a slice preparation in culture. In another embodiment of the method,the agent suppresses inhibition of LTP by soluble Aβ.

Also provided is a method of identifying an agent that suppressesamyloid-mediated inhibition of LTP, comprising identifying an agent asan integrin subunit αv binding agent; and determining that theidentified αv binding agent suppresses amyloid-mediated inhibition ofLTP. In an embodiment of the method, the step of identifying an agentcomprises one or more of a direct binding assay, a competitive bindingassay and a cell adhesion assay; and wherein the step of determiningthat the identified αv binding agent suppresses amyloid-mediatedinhibition of LTP comprises introducing a high frequency stimulation toa first neural circuit and measuring induction of LTP, introducing ahigh frequency stimulation to a second neural circuit in the presence ofAβ and measuring an inhibition of LTP induction, and introducing a highfrequency stimulation to a third neural circuit in the presence of Aβand the agent, and measuring a suppression of inhibition of LTPinduction.

Also provided is an agent that suppresses amyloid-mediated inhibition ofLTP, identified by the method. In an embodiment, the agent is anantibody.

Further provided is a composition comprising the agent and apharmaceutically acceptable carrier.

Further provided is a method of suppressing amyloid-mediated inhibitionof long-term potentiation (LTP), comprising administering an effectivedosage of the agent identified by the method.

An agent that suppresses amyloid-mediated inhibition of LTP, identifiedby the method is also provided. In an embodiment, the agent is anantibody.

A composition comprising the agent and a pharmaceutically acceptablecarrier is also provided.

A method of suppressing amyloid-mediated inhibition of long-termpotentiation (LTP), comprising administering an effective dosage of theagent identified by the method is also provided.

Also provided is a method of treating an amyloidogenic diseasecharacterized by Aβ deposition, comprising administering an αvantagonist or an inhibitor of αv-mediated cell adhesion in an amounteffective to suppress amyloid-mediated inhibition of long-termpotentiation (LTP). In an embodiment, the amyloidogenic disease isAzheimer's disease. In another embodiment the amyloidgenic disease ismild cognitive impairment.

Also provided is method of treating or preventing an amyloidogenicdisease characterized by Aβ deposition, comprising administering aneffective dosage of one or more agents that bind to integrin subunit αvunder conditions such that the one or more agents suppressamyloid-mediated inhibition of LTP. In an embodiment, the amyloidogenicdisease is Alzheimer's disease or mild cognitive impairment. In anembodiment, the amyloidogeic disease is Parkinson's disease or diffuselewy body disease.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates the Aβ meshwork in human cortical cultures (HCC)(top) or polyethyleneimine (PEI) (bottom) coated plates.

FIG. 2 illustrates the effects of β1 integrin subunit on both Aβmeshwork formation and neurotoxicity in HCC. FIG. 2A illustrates β1integrin subunit expression in HCC. FIG. 2B illustrates 72 hour Aβmeshwork formation in HCC in the absence (top) or presence (bottom) ofthe anti-β1 antibody, 1965. FIG. 2C illustrates the inhibition ofneurotoxicity in HCC preincubated with β1 integrin subunit blockingantibodies. Error bars represent standard deviation from (n=3) wells.

FIG. 3A illustrates the effects of α2 and αv integrin subunits on Aβmeshwork formation and neurotoxicity in HCC. FIG. 3B illustrates 72 hourAβ meshwork formation in HCC preincubated in the absence (top) orpresence of anti-α2 (middle) or anti-αv (bottom) antibodies. FIG. 3Cillustrates the neurotoxicity in HCC preincubated with β1 integrinsubunit blocking antibodies.

FIG. 4 illustrates α2 and αv expression in HCC.

FIG. 5 illustrates the effects of anti-laminin antibodies in inhibitingAβ meshwork formation and neurotoxicity. FIG. 5A illustrates 72 hour Aβmeshwork formation in HCC preincubated in the absence (top) or presenceof anti-laminin antibody (bottom). FIG. 5B illustrates neurotoxicity inHCC preincubated with anti-laminin antibodies. Error bars representstandard deviation from (n=3) wells. FIG. 5C illustrates neurotoxicityin HCC preincubated with anti-collagen antibodies. Error bars representstandard deviation from (n=3) wells.

FIG. 6 illustrates activation of the Aβ signaling pathway in HCC. FIG.6A illustrates tyrosine phosphorylation of focal adhesion kinase(Fak)-associated paxillin in Aβ treated HCC. FIG. 6B illustratestyrosine phosphorylation of proline-rich tyrosine kinase(Pyk2)-associated paxillin in Aβ treated HCC.

FIG. 7 illustrates toxicity after 1 day when human cortical neurons areseeded for 1 hour followed by aspiration and treatment with solubleamylin. Integrin or integrin subunit antibodies can be added to thecells in the presence of the seed and soluble amylin to inhibittoxicity. Seed and soluble amylin alone are not toxic. However, if cellsare seeded for 1 hour followed by aspiration and treatment with amylin,the amylin is toxic.

FIG. 8 illustrates that integrin and integrin subunit antibodies,particularly, anti-laminin, anti-β1, anti-αv and anti-a2 antibodiesprotect against amylin toxicity.

FIGS. 9A and 9B illustrate the effect of integrin or integrin subunitantibodies, including anti-αvβ3 anti-αv; and cytochalasin D, inprotecting against amylin toxicity as demonstrated by the percentinhibition of amylin 2 component toxicity after cells are exposed for 1hour to the seed amylin.

FIG. 10A illustrates that anti-αv integrin antibody 18C7 suppresses theinhibition of LTP by synthetic Aβ in the dentate gyrus in vitro. FIG.10B illustrates that anti-αv integrin antibody 20A9 suppresses theinhibition of LTP by synthetic Aβ in the dentate gyrus in vitro. FIG.10C illustrates that anti-αv integrin antibody 17E6 suppresses theinhibition of LTP by synthetic Aβ in the dentate gyrus in vitro.

FIG. 11A illustrates that control anti-αv antibody 27/1 did not preventthe suppression of LTP by Aβ. FIG. 11B illustrates that control anti-αvantibody 7H10 did not prevent the suppression of LTP by Aβ.

FIG. 12A illustrates that soluble Aβ inhibits LTP in the CA1 area invivo. FIG. 12B illustrates that that an anti-αv integrin antibody 17E6suppresses inhibition of LTP by soluble Aβ in the CA1 area in vivo. FIG.12C illustrates that that SM256 suppresses inhibition of LTP by solubleAβ in the CA1 area in vivo.

FIG. 13A illustrates that αv-containing integrin ligand SM256 suppressesinhibition of LTP by Aβ. FIG. 13B illustrates that αv-containingintegrin ligand superfibronectin suppresses inhibition of LTP by Aβ.FIG. 13C illustrates that αv-containing integrin ligand echistatinsuppresses inhibition of LTP by Aβ.

DEFINITIONS

Therapeutic agents of the invention are typically substantially purifiedfrom undesired contaminants. This means that an agent is typically atleast about 50% w/w (weight/weight) purity, as well as beingsubstantially free from interfering proteins and contaminants. Sometimesthe agents are at least about 60%, 70%, 80%, 90%, or 95% w/w purity.Using conventional protein purification techniques, homogenous peptidesof at least 99% w/w can also be obtained.

Specific binding between two entities means an affinity of at least 10⁶,10⁷, 10⁸, 10⁹, or 10¹⁰ M⁻¹. In one embodiment, affinities are greaterthan about 10⁸ M⁻¹.

The term “antibody” or “immunoglobulin” is used to include intactantibodies and binding fragments thereof. Typically, fragments competewith the intact antibody from which they were derived for specificbinding to an antigen fragment including separate heavy chains, lightchains Fab, Fab′, F(ab′)₂, F(ab)c, and Fv. Fragments may be produced byrecombinant DNA techniques, or by enzymatic or chemical separation ofintact immunoglobulins. The term “antibody” also includes one or moreimmunoglobulin chains that are chemically conjugated to, or expressedas, fusion proteins with other proteins. The term “antibody” alsoincludes bispecific antibody. A bispecific or bifunctional antibody isan artificial hybrid antibody having two different heavy/light chainpairs and two different binding sites. Bispecific antibodies can beproduced by a variety of methods including fusion of hybridomas orlinking of Fab′ fragments (See, e.g., Songsivilai and Lachmann, Clin.Exp. Immunol., 79:315-321 (1990); Kostelny et al., J. Immunol.,148:1547-53 (1992)).

APP⁶⁹⁵, APP⁷⁵¹, and APP⁷⁷⁰ refer, respectively, to the 695, 751, and 770amino acid residue long polypeptides encoded by the human APP gene. SeeKang et al., Nature, 325:733-36 (1987); Ponte et al., Nature, 331:525-27(1988); and Kitaguchi et al., Nature, 331:530-32 (1988). Amino acidswithin the human amyloid precursor protein (APP) are assigned numbersaccording to the sequence of the APP⁷⁷⁰ isoform. Terms such as Aβ39,Aβ40, Aβ41, Aβ42, and Aβ43 refer to an Aβ peptide containing amino acidresidues 1-39, 1-40, 1-41, 1-42, and 1-43. Aβ42 has the sequence (SEQ IDNO:1):

H2N-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-Leu-Val-Phe-Phe-Ala-Glu-Asp-Val-Gly-Ser-Asn-Lys-Gly-Ala-IIe-IIe-Gly-Leu-Met-Val-Gly-Gly-Val-Val-IIe-Ala-OH.Aβ41 (SEQ ID NO:3), Aβ40 (SEQ ID NO:4), and Aβ39 (SEQ ID NO:5) differfrom Aβ42 (SEQ ID NO:1) by the omission of Ala, Ala-IIe, andAla-IIe-Val, respectively, from the C-terminal end. Aβ43 (SEQ ID NO:2)differs from Aβ42 (SEQ ID NO:1) by the presence of a threonine residueat the C-terminus.

“Amylin” refers to the protein known commonly in the art or to a peptideor polypeptide or fragment thereof, or to a precursor protein or polymerof the protein, peptide or polypeptide. The term encompasses isletamyloid polypeptide. A description of amylin may be found in the art insuch places as Cooper et al., Proc. Natl. Acad. Sci. U.S.A., 85:7763(1988) and Leighton et al., Nature, 335:632 (1988).

The term “amyloid peptide or protein” refers to the family of peptidesand proteins that form amyloid-like deposits, including amylin and Aβ.

The phrase “amyloid or amyloid-like deposits” includes amyloid fibrilsas well as other amyloid or amyloid-like deposits, fibrillar ornonfibrillar in structure, which are recognized in the art as beingamyloid or amyloid-like, such as deposits in senile amyloidosis (e.g.,Aβ), prion-related encephalopathies (e.g., PrP), and in the kidney orpancreas of diabetic patients (e.g., amylin), etc. On light microscopywith conventional stains, such deposits have a homogeneous, eosinophilicappearance. With Congo red staining, they show a characteristicyellow-green birefringence under polarized light. The term also includespre-amyloid deposits, which unlike amyloid deposits, do not stain withCongo Red.

The term “amyloidogenic disease” is intended to encompass a diseasecharacterized by unwanted deposition of a protein or peptide. The termspecifically encompasses diseases characterized by unwanted depositionof amyloid peptides such as occurs in type II diabetes (e.g., amylin),Alzheimer's disease (e.g., Aβ), multiple myeloma, and rheumatoidarthritis, as described by Kahn et al., Diabetes, 48:241-253 (1999); andJohnson et al., Laboratory Investigation, 66(5):522-535 (1992). The termalso specifically encompasses diseases characterized by unwanteddeposition of amyloidogenic proteins such as Parkinson's disease orhereditary or systemic amyloidoses as described by Hund et al.,Neurology, 56:431-435 (2001) including those mediated by transthyretin(TTR) deposition. The term also includes diffuse lewy body disease.Moreover, the term includes diseases caused all or in part by infectionwith a prion such as Creutzfeldt-Jakob disease. Such prion mediateddiseases are characterized by accumulation of a prion protein asdescribed by Giese et al., Curr. Topics Microbiology and Immunology,253:203-217 (2001). In short, the term is meant to include all diseaseswherein the pathology is mediated by unwanted protein or peptidedeposits that adversely affect the health and well-being of surroundingcells.

An “antigen” is an entity to which an antibody specifically binds.

The term “epitope” or “antigenic determinant” refers to a site on anantigen to which B and/or T cells respond. B-cell epitopes can be formedboth from contiguous amino acids or noncontiguous amino acids juxtaposedby tertiary folding of a protein. Epitopes formed from contiguous aminoacids are typically retained on exposure to denaturing solvents whereasepitopes formed by tertiary folding are typically lost on treatment withdenaturing solvents. An epitope typically includes at least 3, and moreusually, at least 5 or 8-10 amino acids in a unique spatialconformation. Methods of determining spatial conformation of epitopesinclude, for example, x-ray crystallography and 2-dimensional nuclearmagnetic resonance. See, e.g., Epitope Mapping Protocols, in Methods inMolecular Biology, Vol. 66, Glenn E. Morris, Ed. (1996). Antibodies thatrecognize the same or overlapping epitopes can be identified in a simpleimmunoassay showing the ability of one antibody to block the binding ofanother antibody to a target antigen.

The term “naked polynucleotide” or “naked DNA” refers to apolynucleotide not complexed with colloidal materials, e.g., proteins.Naked polynucleotides are sometimes cloned in a plasmid vector.

The term “patient” includes human and other mammalian subjects thatreceive either prophylactic or therapeutic treatment.

The term “prevent,” “preventing” and “prevention” refers to theadministration of therapy on a prophylactic or preventative basis to anindividual who may ultimately manifest at least one symptom of a diseaseor condition (e.g., suppression of long-term potentiation and/orneurodegeneration) but who has not yet done so. Such individuals may beidentified on the basis of risk factors that are known to correlate withthe subsequent occurrence of the disease. Alternatively, preventiontherapy may be administered without prior identification of a riskfactor, as a prophylactic measure. Delaying the onset of the at leastone symptom of the disease or condition may also be consideredprevention or prophylaxis.

As used herein, the term “treat,” “treating” or “treatment” refers tothe administration of therapy to an individual who already manifests atleast one symptom of a disease or condition (e.g., suppression oflong-term potentiation and/or neurodegeneration).

“Co-administration” of an agent and a secondary agent includesadministration by any dosing regimen to achieve therapeuticconcentrations of the agent and secondary agent that overlap in time, inan in vitro system or in vivo, such as in a patient. Thus, for example,co-administration includes administration of a formulation comprisingboth the agent and the secondary agent, as well as administration ofseparate formulations, one comprising the agent and another comprisingthe secondary agent. When separate formulations are administered,administration may be simultaneous or in series. If in series, theagents may be administered one right after the other, or the timebetween administration of the agent and administration of the secondaryagent may be up to 1 hour, up to 2 hours, up to 4 hours, up to 6 hours,up to 12 hours, or up to 1 day or several days, for example.

Neuronal cells can be exposed to Aβ peptide as a result of the naturalprocessing of APP to Aβ that occurs in vivo, or as a result ofcontacting the neuronal cells with a preparation of Aβ in an in vitroassay. Exposure to Aβ peptide can occur before, after, or at the sametime as exposure to drugs.

Amyloid deposits of Aβ peptide refer to aggregates of the Aβ peptides,possibly including fibrils, that form on and around cortical cells invitro, such as shown in FIG. 1A, or in vivo.

Unless otherwise apparent from the context, reference to fibronectinincludes superfibronectin.

Competition between antibodies is determined by an assay in which theimmunoglobulin under test inhibits specific binding of a referenceantibody to a common antigen. Numerous types of competitive bindingassays are known, for example: solid phase direct or indirectradioimmunoassay (RIA), solid phase direct or indirect enzymeimmunoassay (EIA), sandwich competition assay (see Stahli et al.,Methods in Enzymology, 9:242-53 (1983)); solid phase directbiotin-avidin EIA (see Kirkland et al., J. Immunol., 137:3614-19(1986)); solid phase direct labeled assay, solid phase direct labeledsandwich assay (see Harlow and Lane, “Antibodies, A Laboratory Manual,”Cold Spring Harbor Press (1988)); solid phase direct label RIA using1-125 label (see Morel et al., Molec. Immunol., 25(1):7-15 (1988));solid phase direct biotin-avidin EIA (Cheung et al., Virology,176:546-52 (1990)); and direct labeled RIA (Moldenhauer et al., Scand.J. Immunol., 32:77-82 (1990)). Typically, such an assay involves the useof purified antigen bound to a solid surface or cells bearing either anunlabelled test immunoglobulin or a labeled reference immunoglobulin.Competitive inhibition is measured by determining the amount of labelbound to the solid surface or cells in the presence of the testimmunoglobulin. Usually the test immunoglobulin is present in excess.Antibodies identified by competition assay (competing antibodies)include antibodies binding to the same epitope as the reference antibodyand antibodies binding to an adjacent epitope sufficiently proximal tothe epitope bound by the reference antibody for steric hindrance tooccur. Usually, when a competing antibody is present in excess, it willinhibit specific binding of a reference antibody to a common antigen byat least 50 or 75%.

Compositions or methods “comprising” one or more recited elements mayinclude other elements not specifically recited. For example, acomposition that comprises antibody may contain the antibody alone or incombination with other ingredients.

DESCRIPTION OF THE INVENTION I. Methods

The invention provides methods of inhibiting or preventing formation ofextracellular meshworks of amyloid proteins, such as amylin and Aβpeptide, methods for mediating the toxic effects of such proteins, andagents for use in the methods. The methods can be used to treat orprevent Alzheimer's disease, type II diabetes, Parkinson's disease,diffuse lewy body disease, systemic and hereditary amyloidoses, as wellas diseases caused all or in part by prion infection. Agents effectivefor use in these methods include antibodies and other agents that bindto an integrin subunit such as β1, α2, α6, or αv. These subunitsassociate as heterodimeric receptors to form integrins, e.g., α2β1,α6β1, and αvβ1. The above agents can be used individually or incombinations to inhibit interaction between integrins and the Aβpeptide. Use of an agent or agents that inhibit interactions betweenboth αvβ1 and α2β1 integrins and Aβ is preferred. Fibronectin, a ligandof integrin, αvβ1, can also be used as an agent, as can antibodies tolaminin, a ligand of αvβ1 in the above methods. The invention ispremised, in part, on the observation that antibodies to α2, αv, α6 andβ1 integrin subunits inhibit formation of extracellular meshworks ofamyloid proteins, such as amylin and Aβ peptide. Thereby, suchantibodies inhibit the toxicity of amyloid proteins. The αvβ1 ligand,fibronectin, also inhibits meshwork formation. The α2β1 ligand, laminin,does not inhibit meshwork formation but antibodies to laminin do inhibitmeshwork formation and toxicity.

The invention is further premised, in part, on the observation thatselective antibodies to the αv integrin subunit suppress inhibition ofLTP by Aβ, both in vitro and in vivo. A small molecule nonpeptideantagonist of αv-containing integrins and two other antagonistic ligandsof integrins, superfibronectin and the disintegrin echistatin, alsosuppress Aβ inhibition of LTP. Thus, agents that bind to the αv integrinsubunit suppress Aβ inhibition of LTP, and inhibit or prevent formationof extracellular meshworks of amyloid proteins, such as amylin and Aβpeptide.

Accordingly, the invention also provides methods for suppressingamyloid-mediated inhibition of long-term potentiation (LTP), and methodsfor treating or preventing amyloidogenic disease characterized by Aβdeposition, as well as methods for treating an amyloidogenic diseasecharacterized by the deposition of Aβ, comprising administering an αvantagonist or an inhibitor of αv-mediated cell adhesion in an amounteffective to suppress amyloid-mediated inhibition of long-termpotentiation (LTP). The methods are useful to treat or prevent diseasesor conditions, including but not limited to, Alzheimer's disease, typeII diabetes, Parkinson's disease, diffuse lewy body disease, systemicand hereditary amyloidoses, as well as diseases caused all or in part byprion infection. Agents effective for use in these methods include, butare not limited to, antibodies and other agents, such as for exampleSM256, that bind to integrin subunit αv. The above agents can be usedindividually or in combinations to inhibit interaction between integrinsand the Aβ peptide.

II. Integrins

Integrins are a superfamily of cell surface adhesion heterodimerictransmembrane receptors, which control the attachment of cells both tothe extracellular matrix and to other cells. Adhesion providesanchorages and signals for growth, migration, and differentiation.Integrins are formed by the association of one of about fifteen knownalpha chains with one of about eight known beta chains. All human cellsbut erythrocytes express one or more integrins.

Integrin subunits α2, αv, α6 and β1 are all well known. Exemplary humansequences are retrievable from GenBank accession numbers AF062039,M14648, X59512 and X07979, respectively. Unless otherwise indicated,reference to α2, αv, α6, β1 includes these exemplary sequences, allelicvariants thereof, and cognate variants from other species. Inducedvariants of these sequences, having sufficient sequence identity to thenatural sequence to compete with the natural sequence for specificbinding to a ligand of the natural sequence, can also be used in somemethods. Integrins containing αv and one of the β subunits β1, β3, β5,β6 or β8 recognize ligands bearing an RGD motif, but the bindingspecificity varies depending on which β subunit is present. αvβ1 isknown to recognize vitronectin (GenBank accession number X03168),fibronectin (GenBank accession number M26179) and osteopontin (GenBankaccession number J04765). Fibronectin is a large multidomainglycoprotein found in connective tissue, on cell surfaces, and in plasmaand other body fluids. Fibronectin acts with a variety ofmacromolecules, including components of the cytoskeleton and theextracellular matrix; circulating components involved in the bloodclotting response, fibrinolytic, acute phase and complement systems, andwith cell-surface receptors on a variety of cells including fibroblasts,neurons, phagocytes, and bacteria.

Integrins containing α2 and β1 subunits are known as VLA-2 (very lateactivation antigen 2), GPIa-IIa (glycoprotein Ia-IIa on platelets), andECMRII (extracellular matrix receptor II). The α2β1 integrins bindcollagen-I to VI, laminin and possibly fibronectin. The receptor isexpressed on B and T lymphocytes, platelets, fibroblasts, endothelialcells, and melanoma cells, and specifically recognizes collagen andlaminins as ligands. Laminins are large, multi domain proteins with acommon structural organization. Laminin molecules have alpha, beta, andgamma chain subunits joined together though a coiled coil domain. Atleast five alpha chains, two beta chains, and three gamma chains areknown, and at least twelve laminins having different combinations ofthese chains have been reported (WO 00/66730). Laminin is found inextracellular matrices including plaques in Alzheimer's disease(Murtomaki, et al., J. Neuro. Res., 32:261-73 (1992); Bronfinan, et al.,Int. J. Exp. Clin. Invest., 5:16-23 (1997); and Castillo, et al., J.Neuro. Res., 62:451-62 (2000)). Collagen is the most abundant protein inmammals and is the main fibrous component of skin, bone, tendon,cartilage, and teeth. There are more than 23 known collagen genes (Adamset al., Am. J. Respir. Cell. Molec. Biol., 1:161-168 (1989)).

The α6/β1 integrin is expressed on platelets, lymphocytes, monocytes,thymocytes, and epithelial cells, on which it functions as a lamininreceptor for laminin-1, laminin-2, and laminin-4 in vivo. It is also areceptor for laminin-5, but not in vivo. For laminin-1, the binding sitehas been localized in the E8 domain of this extracellular matrixmolecule. This receptor is also known as very late activation antigen 6(VLA-6) and glycoprotein Ic-IIa (GPIc-IIa on platelets).

Integrins are an example of a larger class of proteins known as adhesionproteins that also includes selectins and immunoglobulin (Ig)superfamily members (see Springer, Nature, 346:425 (1990); Osborn, Cell,62:3 (1990); Hynes, Cell, 69:11 (1992), which are incorporated byreference in their entirety for all purposes). Antibodies and otheragents that bind to adhesion proteins or their ligands, and/or blockinteraction between the two, can be screened for activity in preventingor inhibiting the accumulation of Aβ deposits in the methods ofscreening described below. Examples of other selectins and their ligandssuitable for screening by the methods described below include integrinsα2β5, αvβ5, α6β5, α2β6, αvβ6, and α6β6. Other ligands besides α2β1 thatbind to collagen may also be screened.

III. Agents

Therapeutic agents of the invention include antibodies that specificallybind to α2, αv, α6, and β1 integrin subunits. Binding can be assessedeither with isolated integrin subunits or fragments thereof, optionallyimmobilized to a solid phase, or with integrin subunits expressed on thesurface of cells. Often, binding is analyzed using cells expressing aheterodimeric integrin. For example, if an agent binds to cellsexpressing α2β1 as the only integrin, then it can be concluded that theagent binds to α2 or β1 or to α2β1 without binding to either subunitalone. These possibilities can be distinguished by testing binding ofthe same agent to cells bearing a different heterodimeric integrin. Forexample, if the same agent specifically binds to cells bearing αvβ1 asthe only integrin present, then it is likely that the agent is bindingto the β1 subunit. A variety of antibodies to integrin and integrinsubunits are commercially available, some of which are described in theExamples.

Monoclonal or polyclonal antibodies can be used in the methods of theinvention. Preferred antibodies block interaction of these integrinsubunits with one or more of their natural ligands. That is, blockingantibodies to αvβ1 block interaction of this integrin with fibronectin,osteopontin and/or vitronectin. For example, the 14D9.F8 antibodydescribed by WO 99/37683 blocks binding of αv to fibronectin. Blockingantibodies to α2β1 block interaction of this integrin with collagen orlaminin. The capacity of an antibody or other agent to block can berecognized by a simple assay in which cells expressing an integrin aretested for adhesion to a plate coated with ligand in the presence orabsence of antibody (or other agent). A reduction of at least about 30%,40%, 50%, 60%, 70%, 80%, 90%, or 100% of the amount of cells binding tothe plate identifies a blocking antibody (or other agent) when theantibody is present in molar excess relative to the integrin. Furtheranalyses of the blocking capacity of the agent to other combinations ofintegrin subunits can pinpoint which subunit of a heterodimeric integrinis being blocked. Binding specificity of an antibody or other agent canalso be determined by a competition assay in which a test antibodycompetes with a reference antibody known to have the desired epitopespecificity for binding to an integrin subunit or cells bearing thesame. If the test and reference antibodies compete, then they bind tothe same epitope or epitopes sufficiently proximal that binding of oneantibody interferes with binding of the other. In some embodiments,transfected cells express a single type of integrin.

Some antibodies for use in the invention bind to only one type ofintegrin subunit. Some antibodies specifically bind to two or moreintegrin subunits. Some antibodies bind only when the subunits of anintegrin are associated as a heterodimeric integrin. For example, someantibodies bind to α2β1 without binding to either α2 or β1 alone. Someantibodies bind to αvβ1 without binding to either αv or β1 alone. Someantibodies bind to the αv integrin subunit. Some antibodies bind tosubunits both in free form and when the subunit is a component of aheterodimeric integrin. Peptides and small molecules that have the samebinding specificity of the above antibodies can also be used.

Other therapeutic agents for use in the invention include fibrinogen,osteopontin, vitronectin, fragments thereof, and other natural orsynthetic peptides containing an RGD peptide motif that competes withfibrinogen or vitronectin for binding to αvβ1. Small molecule mimeticsthat compete with fibrinogen, vitronectin, or osteopontin for binding toαvβ1 can also be used. Other therapeutic agents include antibodies tolaminin, and peptides and small molecules with the same bindingspecificity.

Candidate therapeutic agents can be evaluated by performing one or moreof the following screens. Typically, agents are first evaluated forspecific binding to an integrin subunit, α2, αv, α6, or β1, and/or aheterodimeric integrin α2β1, αvβ1 α6β1, or laminin. Suitable agentstypically bind with specific affinities of at least 10⁷, 10⁸, 10⁹ or10¹⁰ M⁻¹.

Thereafter, candidates are optionally evaluated for a particular epitopespecificity. This can be determined by a competition assay with areference agent, by a functional plate blocking assay as describedabove, or by an epitope mapping experiment in which an antibody or otheragent is evaluated by Western blotting or ELISA for its capacity to binda series of deletion mutants of an antigen. The smallest fragment toshow specific binding to the antibody or other agent defines the epitopeof the antibody or other agent. Alternatively, or additionally,candidate agents are evaluated for the capacity to inhibit formation ofextracellular meshworks of amyloid peptides. Suitable agents typicallyreduce toxicity resulting from treatment with amyloid peptides, such asamylin or Aβ, in the presence of an agent relative to a control by atleast about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% ormore.

Candidate compounds can also be tested for prophylactic and therapeuticefficacy in transgenic animals predisposed to an amyloidogenic disease.Such animals include, for example, mice bearing a 717 mutation of APPdescribed by Games et al., supra, and mice bearing a 670/671 Swedishmutation of APP such as described by McConlogue et al., U.S. Pat. No.5,612,486; Hsiao et al., Science, 274:99 (1996); Sturchler-Plerrat etal., Proc. Natl. Acad. Sci. U.S.A., 94:13287-92 (1997); and Borchelt etal., Neuron, 19:939-45 (1997). Agents showing activity in transgenicmice can then be evaluated in human clinical trials. Exemplary formatsfor conducting human clinical trials in Alzheimer's patients aredescribed in WO 98/24678, which is incorporated herein by reference.

In the case of candidate compounds for use in methods of suppressingamyloid-mediated inhibition of long-term potentiation (LTP), thecompound may be tested in an in vitro and/or an in vivo model of LTP.For example, a candidate compound may be first tested in an in vitromodel, and then, if the compound suppresses amyloid-mediated inhibitionof long-term potentiation (LTP) in that model, tested subsequently in anin vivo model.

A. Antibodies 1. General Characteristics of Immunoglobulins

The basic antibody structural unit is known to comprise a tetramer ofsubunits. Each tetramer is composed of two identical pairs ofpolypeptide chains, each pair having one “light” (about 25 kDa) and one“heavy” chain (about 50-70 kDa). The amino-terminal portion of eachchain includes a variable region of about 100 to 110 or more amino acidsprimarily responsible for antigen recognition. The carboxy-terminalportion of each chain defines a constant region primarily responsiblefor effector function.

Light chains are classified as either kappa or lambda. Heavy chains areclassified as gamma, mu, alpha, delta, or epsilon, and define theantibody's isotype as IgG, IgM, IgA, IgD, and IgE, respectively. Withinlight and heavy chains, the variable and constant regions are joined bya “J” region of about 12 or more amino acids, with the heavy chain alsoincluding a “D” region of about 10 more amino acids. (See generally,Fundamental Immunology (Paul, W., Ed., 2nd ed. Raven Press, N.Y., 1989),Ch. 7 (incorporated by reference in its entirety for all purposes).

The variable regions of each light/heavy chain pair form the antibodybinding site. Thus, an intact antibody has two binding sites. Except inbifunctional or bispecific antibodies, the two binding sites are thesame. The chains all exhibit the same general structure of relativelyconserved framework regions (FR) joined by three hypervariable regions,also called complementarity determining regions or CDRs. The CDRs fromthe two chains of each pair are aligned by the framework regions,enabling binding to a specific epitope. From N-terminal to C-terminal,both light and heavy chains comprise the domains FR1, CDR1, FR2, CDR2,FR3, CDR3, and FR4. The assignment of amino acids to each domain is inaccordance with the definitions of Kabat, Sequences of Proteins ofImmunological Interest (National Institutes of Health, Bethesda, Md.,1987 and 1991), or Chothia & Lesk, J. Mol. Biol., 196:901-17 (1987);Chothia et al., Nature, 342:878-83 (1989).

2. Production of Nonhuman Antibodies

The production of nonhuman monoclonal antibodies, e.g., murine, guineapig, primate, rabbit, or rat, can be accomplished by, for example,immunizing the animal with an integrin, subunits thereof, or fragmentsthereof, or with cells bearing the integrin or a subunit thereof.Laminin can also be used as an immunogen for generating antibodies tolaminin. See Harlow & Lane, Antibodies, A Laboratory Manual (Cold SpringHarbor Press, NY, 1988, incorporated herein by reference for allpurposes). Such an immunogen can be obtained from a natural source, bypeptide synthesis, or by recombinant expression. Optionally, theimmunogen can be administered fused or otherwise complexed with acarrier protein, as described below. Optionally, the immunogen can beadministered with an adjuvant. Several types of adjuvant can be used asdescribed below. Complete Freund's adjuvant followed by incompleteadjuvant is preferred for immunization of laboratory animals. Rabbits,goats, sheep, or guinea pigs are typically used for making polyclonalantibodies. Mice are typically used for making monoclonal antibodies.Antibodies are screened for specific binding to the intended integrin orsubunit thereof, or other antigen such as laminin. Antibodies can alsobe screened for the capacity to block binding of an integrin to itsligand as described above. Other screening procedures described abovecan also be conducted.

3. Chimeric and Humanized Antibodies

Chimeric and humanized antibodies may have the same or similar bindingspecificity and affinity as a mouse or other nonhuman antibody thatprovides the starting material for construction of a chimeric orhumanized antibody. Some chimeric or humanized antibodies haveaffinities within a factor of 2-fold, 5-fold or 10-fold that of a mouse.Chimeric antibodies are antibodies whose light and heavy chain geneshave been constructed, typically by genetic engineering, fromimmunoglobulin gene segments belonging to different species. Forexample, the variable (V) segments of the genes from a mouse monoclonalantibody may be joined to human constant (C) segments, such as IgG1,IgG2, IgG3, or IgG4. A typical chimeric antibody is thus a hybridprotein consisting of the V or antigen-binding domain from a mouseantibody and the C or effector domain from a human antibody.

Humanized antibodies have variable region framework residuessubstantially from a human antibody (termed an acceptor antibody) andcomplementarity determining regions substantially from a nonhumanantibody such as a mouse-antibody, (referred to as the donorimmunoglobulin). See Queen et al., Proc. Nat. Acad. Sci. U.S.A.,86:10029-33 (1989) and WO 90/07861, U.S. Pat. No. 5,693,762, U.S. Pat.No. 5,693,761, U.S. Pat. No. 5,585,089, U.S. Pat. No. 5,530,101, andWinter, U.S. Pat. No. 5,225,539 (each of which are incorporated hereinby reference in their entirety for all purposes). The constant region,if present, is also substantially or entirely from a humanimmunoglobulin. The human variable domains are usually chosen from humanantibodies whose framework sequences exhibit a high degree of sequenceidentity with the murine variable region domains from which the CDRswere derived. The heavy and light chain variable region frameworkresidues can be derived from the same or different human antibodysequences. The human antibody sequences can be the sequences ofnaturally occurring human antibodies or can be consensus sequences ofseveral human antibodies. See Carter et al., WO 92/22653. Certain aminoacids from the human variable region framework residues are selected forsubstitution based on their possible influence on CDR conformationand/or binding to antigen. Investigation of such possible influences isby modeling, examination of the characteristics of the amino acids atparticular locations, or empirical observation of the effects ofsubstitution or mutagenesis of particular amino acids.

For example, when an amino acid differs between a murine variable regionframework residue and a selected human variable region frameworkresidue, the human framework amino acid should usually be substituted bythe equivalent framework amino acid from the mouse antibody when it isreasonably expected that the amino acid:

(1) noncovalently binds antigen directly,

(2) is adjacent to a CDR region,

(3) otherwise interacts with a CDR region (e.g., is within about 6angstroms of a CDR region), or

(4) participates in the VL-VH interface.

Other candidates for substitution are acceptor human framework aminoacids that are unusual for a human immunoglobulin at that position.These amino acids can be substituted with amino acids from theequivalent position of the donor antibody or from the equivalentpositions of more typical human immunoglobulins. The variable regionframeworks of humanized immunoglobulins usually show at least 85%sequence identity to a human variable region framework sequence orconsensus of such sequences.

4. Human Antibodies

Human antibodies against the above integrins or laminin are provided bya variety of techniques described below. Some human antibodies areselected by competitive binding experiments, or otherwise, to have thesame epitope specificity as a particular mouse antibody, such as one ofthe mouse monoclonals described in the Examples. Human antibodies canalso be screened for a particular epitope specificity by using only afragment of an integrin or laminin as the immunogen, and/or by screeningantibodies against a collection of deletion mutants of the integrin.

a. Trioma Methodology

The basic approach and an exemplary cell fusion partner, SPAZ-4, for usein this approach have been described by Oestberg et al., Hybridoma,2:361-67 (1983); Oestberg, U.S. Pat. No. 4,634,664; and Engleman et al.,U.S. Pat. No. 4,634,666 (each of which is incorporated herein byreference in its entirety for all purposes). The antibody-producing celllines obtained by this method are called triomas, because they aredescended from three cells—two human and one mouse. Initially, a mousemyeloma line is fused with a human B-lymphocyte to obtain anonantibody-producing xenogeneic hybrid cell, such as the SPAZ-4 cellline described by Oestberg, supra. The xenogeneic cell is then fusedwith an immunized human B-lymphocyte to obtain an antibody-producingtrioma cell line. Triomas have been found to produce antibody morestably than ordinary hybridomas made from human cells.

The immunized B-lymphocytes are obtained from the blood, spleen, lymphnodes, or bone marrow of a human donor. If antibodies against a specificantigen or epitope are desired, it is preferable to use that antigen oran epitope thereof for immunization. Immunization can be either in vivoor in vitro. For in vivo immunization, B cells are typically isolatedfrom a human immunized with Aβ, a fragment thereof, larger polypeptidecontaining Aβ or fragment, or an anti-idiotypic antibody to an antibodyto A. In some methods, B cells are isolated from the same patient who isultimately to be administered antibody therapy. For in vitroimmunization, B-lymphocytes are typically exposed to antigen for aperiod of 7-14 days in a medium such as RPMI-1640 (see Engleman, supra)supplemented with 10% human plasma.

The immunized B-lymphocytes are fused to a xenogeneic hybrid cell suchas SPAZ-4 by well known methods. For example, the cells are treated with40-50% polyethylene glycol of MW 1000-4000, at about 37° C., for about5-10 min. Cells are separated from the fusion mixture and propagated inmedium selective for the desired hybrids (e.g., containingHypoxanthine+Amethopterin+Thymidine (HAT Media) orAmethopterin+Hypoxanthine (AH Media)). Clones secreting antibodieshaving the required binding specificity are identified by assaying thetrioma culture medium for the ability to bind to Aβ or a fragmentthereof. Triomas producing human antibodies having the desiredspecificity are subcloned by the limiting dilution technique and grownin vitro in culture medium. The trioma cell lines obtained are thentested for the ability to bind Aβ or a fragment thereof.

Although triomas are genetically stable they do not produce antibodiesat very high levels. Expression levels can be increased by cloningantibody genes from the trioma into one or more expression vectors, andtransforming the vector into standard mammalian, bacterial, or yeastcell lines.

b. Transgenic Non-Human Mammals

Human antibodies against integrins or laminin can also be produced fromnon-human transgenic mammals having transgenes encoding at least asegment of the human immunoglobulin locus. Usually, the endogenousimmunoglobulin locus of such transgenic mammals is functionallyinactivated. Preferably, the segment of the human immunoglobulin locusincludes non-rearranged sequences of heavy and light chain components.Both the inactivation of endogenous immunoglobulin genes and theintroduction of exogenous immunoglobulin genes can be achieved by thetargeted homologous recombination, or by introduction of yeastartificial chromosomes (YACs). The transgenic mammals resulting fromthis process are capable of functionally rearranging the immunoglobulincomponent sequences, and expressing a repertoire of antibodies ofvarious isotypes encoded by human immunoglobulin genes, withoutexpressing endogenous immunoglobulin genes. The production andproperties of mammals having these properties are described in detailby, e.g., Lonberg et al., WO93/12227 (1993); U.S. Pat. No. 5,877,397,U.S. Pat. No. 5,874,299, U.S. Pat. No. 5,814,318, U.S. Pat. No.5,789,650, U.S. Pat. No. 5,770,429, U.S. Pat. No. 5,661,016, U.S. Pat.No. 5,633,425, U.S. Pat. No. 5,625,126, U.S. Pat. No. 5,569,825, U.S.Pat. No. 5,545,806, Nature 148, 1547-53 (1994), Fishwild et al., NatureBiotechnology, 14, 845-51 (1996), Kucherlapati, WO 91/10741 (1991) (eachof which is incorporated by reference in its entirety for all purposes).Transgenic mice are particularly suitable. Anti-integrin or anti-lamininantibodies are obtained by immunizing a transgenic nonhuman mammal, suchas described by Lonberg or Kucherlapati, supra, with an integrin orsubunit or a fragment thereof. Monoclonal antibodies are prepared by,e.g., fusing B-cells from such mammals to suitable myeloma cell linesusing conventional Kohler-Milstein technology. Human polyclonalantibodies can also be provided in the form of serum from humansimmunized with an immunogenic agent. Optionally, such polyclonalantibodies can be concentrated by affinity purification using anintegrin or laminin as an affinity reagent.

c. Phage Display Methods

A further approach for obtaining human anti-integrin or anti-lamininantibodies is to screen a DNA library from human B cells according tothe general protocol outlined by Huse et al., Science, 246:1275-81(1989). As described for trioma methodology, such B cells can beobtained from a human immunized with an integrin, subunits, or fragmentsthereof, or laminin and fragments thereof. Optionally, such B cells areobtained from a patient who is ultimately to receive antibody treatment.Antibodies binding to an antigen of interest or a fragment thereof areselected. Sequences encoding such antibodies (or binding fragments) arethen cloned and amplified. The protocol described by Huse is renderedmore efficient in combination with phage-display technology. See, e.g.,Dower et al., WO 91/17271 and McCafferty et al., WO 92/01047, U.S. Pat.No. 5,877,218, U.S. Pat. No. 5,871,907, U.S. Pat. No. 5,858,657, U.S.Pat. No. 5,837,242, U.S. Pat. No. 5,733,743, U.S. Pat. No. 5,565,332,U.S. Pat. No. 5,969,108, U.S. Pat. No. 6,172,197 (each of which isincorporated herein by reference in its entirety for all purposes).Additional methods for selecting and labeling antibodies, or otherproteins, that bind to a particular ligand are described by U.S. Pat.No. 5,994,519 and U.S. Pat. No. 6,180,336.

In phage display methods, libraries of phage are produced in whichmembers display different antibodies on their outer surfaces. Antibodiesare usually displayed as Fv or Fab fragments. Phage displayingantibodies with a desired specificity are selected by affinityenrichment to an integrin, subunit, or fragment thereof.

In a variation of the phage display method, human antibodies having thebinding specificity of a selected murine antibody can be produced. SeeWinter, WO 92/20791. In this method, either the heavy or light chainvariable region of the selected murine antibody is used as a startingmaterial. If, for example, a light chain variable region is selected asthe starting material, a phage library is constructed in which membersdisplay the same light chain variable region (i.e., the murine startingmaterial) and a different heavy chain variable region. The heavy chainvariable regions are obtained from a library of rearranged human heavychain variable regions. A phage showing strong specific binding for Aβ(e.g., at least about 10⁸ or at least about 10⁹ M⁻¹) is selected. Thehuman heavy chain variable region from this phage then serves as thestarting material for constructing a further phage library. In thislibrary, each phage displays the same heavy chain variable region (i.e.,the region identified from the first display library) and a differentlight chain variable region. The light chain variable regions areobtained from a library of rearranged human variable light chainregions. Again, phage showing strong specific binding for a desiredintegrin are selected. These phage display the variable regions ofcompletely human anti-integrin antibodies. These antibodies usually havethe same or similar epitope specificity as the murine starting material.

5. Selection of Constant Region

The heavy and light chain variable regions of chimeric, humanized, orhuman antibodies can be linked to at least a portion of a human constantregion. The choice of constant region depends, in part, on whetherantibody-dependent complement and/or cellular mediated toxicity isdesired. For example, isotypes IgG1 and IgG3 have complement activityand isotypes IgG2 and IgG4 do not. Choice of isotype can also affectpassage of the antibody into the brain. Light chain constant regions canbe lambda or kappa. Antibodies can be expressed as tetramers containingtwo light and two heavy chains, as separate heavy chains, light chains,as Fab, Fab′, F(ab′)₂, and Fv, or as single chain antibodies in whichheavy and light chain variable domains are linked through a spacer.

6. Expression of Recombinant Antibodies

Chimeric, humanized, and human antibodies are typically produced byrecombinant expression. Recombinant polynucleotide constructs typicallyinclude an expression control sequence operably linked to the codingsequences of the antibody chains, including naturally-associated orheterologous promoter regions. Preferably, the expression controlsequences are eukaryotic promoter systems in vectors capable oftransforming or transfecting eukaryotic host cells. Once the vector hasbeen incorporated into the appropriate host, the host is maintainedunder conditions suitable for high level expression of the nucleotidesequences and for the collection and purification of the crossreactingantibodies.

These expression vectors typically replicate in the host organismseither as episomes or as an integral part of the host chromosomal DNA.Commonly, expression vectors contain selection markers, e.g.,ampicillin-resistance or hygromycin-resistance, to permit detection ofthose cells transformed with the desired DNA sequences.

Escherichia coli is one prokaryotic host particularly useful for cloningthe DNA sequences of the present invention. Microbes, such as yeast arealso useful for expression. Saccharomyces is a preferred yeast host,with suitable vectors having expression control sequences, an origin ofreplication, termination sequences and the like as desired. Typicalpromoters include the 3-phosphoglycerate kinase promoter and promotersfrom other glycolytic enzymes. Inducible yeast promoters include, amongothers, the promoters from alcohol dehydrogenase, isocytochrome C, andthe enzymes responsible for maltose and galactose utilization.

Mammalian cells are a preferred host for expressing nucleotide segmentsencoding immunoglobulins, or fragments thereof. See Winnacker, FromGenes to Clones, (VCH Publishers, NY, 1987). A number of suitable hostcell lines capable of secreting intact heterologous proteins have beendeveloped in the art, and include CHO cell lines, various COS celllines, HeLa cells, L cells, and myeloma cell lines. Preferably, thecells are nonhuman. Expression vectors for these cells can includeexpression control sequences, such as an origin of replication, apromoter, an enhancer (Queen et al., Immunol. Rev., 89:49-68 (1986)),and necessary processing information sites, such as ribosome bindingsites, RNA splice sites, polyadenylation sites, and transcriptionalterminator sequences. Preferred expression control sequences arepromoters derived from endogenous genes, cytomegalovirus, SV40,adenovirus, bovine papillomavirus, and the like. See Co et al., J.Immunol., 148:1149-54 (1992).

Alternatively, antibody coding sequences can be incorporated intransgenes for introduction into the genome of a transgenic animal andsubsequent expression in the milk of the transgenic animal (see, e.g.,U.S. Pat. No. 5,741,957, U.S. Pat. No. 5,304,489, U.S. Pat. No.5,849,992). Suitable transgenes include coding sequences for lightand/or heavy chains in operable linkage with a promoter and enhancerfrom a mammary gland specific gene, such as casein or betalactoglobulin.

The vectors containing the DNA segments of interest can be transferredinto the host cell by well-known methods, depending on the type ofcellular host. For example, calcium chloride transfection is commonlyutilized for prokaryotic cells, whereas calcium phosphate treatment,electroporation, lipofection, biolistics, or viral-based transfectioncan be used for other cellular hosts. Other methods used to transformmammalian cells include the use of polybrene, protoplast fusion,liposomes, and microinjection. For production of transgenic animals,transgenes can be microinjected into fertilized oocytes, or can beincorporated into the genome of embryonic stem cells, and the nuclei ofsuch cells transferred into enucleated oocytes.

Once expressed, antibodies can be purified according to standardprocedures known in the art, including HPLC purification, columnchromatography, gel electrophoresis, and the like (see generally,Scopes, Protein Purification (Springer-Verlag, NY, 1982)).

7. Nanobodies

Nanobodies are heavy-chain antibodies that contain a single variabledomain (VHH) and two constant domains (CH2 and CH3). The cloned andisolated VHH domain is a stable polypeptide harboring the fullantigen-binding capacity of the original heavy-chain antibody.

8. Other Antibodies

Antibodies may also be identified and/or produced by methods such asthose described in U.S. Patent Application Publications Nos.20040038304, 20070020685, 20060257396, 20060160184, 20060134098,20050255552, 20050008625, 20040132066, 20040038317, 20030198971, and20030157579.

B. Other Agents

Agents can be naturally occurring or synthetic molecules. Agents to bescreened can also be obtained from natural sources, such as, e.g.,marine microorganisms, algae, plants, and fungi. For example, U.S. Pat.No. 6,096,707, provides peptides derived from jararhagin, ametalloproteinase from the pit viper Bothrops jararaca. These peptidescontain the amino acid motif Arg-Lys-Lys (RKK), and decrease theinteraction of the human α2 β1 integrin with collagen. Alternatively,agents to be screened can be from combinatorial libraries of agents,including peptides or small molecules, or from existing repertories ofchemical compounds synthesized in industry, e.g., by the chemical,pharmaceutical, environmental, agricultural, marine, cosmeceutical,drug, and biotechnological industries. Agents can include, e.g.,pharmaceuticals, therapeutics, environmental, agricultural, orindustrial agents, pollutants, cosmeceuticals, drugs, organic compounds,lipids, glucocorticoids, antibiotics, peptides, proteins, sugars,carbohydrates, and chimeric molecules.

A variety of methods are available for producing peptide libraries (see,e.g., Lam et al., Nature, 354:92, 1991 and WO 92/00091; Geysen et al.,J. Immunol. Meth., 102:259 (1987); Houghten et al., Nature, 354:84(1991); WO 92/09300; and Lebl et al., Int. J. Pept. Prot Res., 41:201(1993)). Peptide libraries can also be generated by phage displaymethods. See, e.g., Devlin, WO 91/18980.

Combinatorial libraries can be produced for many types of compounds thatcan be synthesized in a step-by-step fashion (see e.g., Ellman & Bunin,J. Amer. Chem. Soc., 114:10997, 1992 (benzodiazepine template), WO95/32184 (oxazolone and aminidine template), WO 95/30642(dihydrobenzopyran template), and WO 95/35278 (pyrrolidine template)).Libraries of compounds are usually synthesized by solid phase chemistry.However, solution-phase library synthesis can also be useful. Strategiesfor combinatorial synthesis are described by Dolle & Nelson, J.Combinatorial Chemistry, 1:235-282 (1999) (incorporated herein byreference in its entirety for all purposes). Synthesis is typicallyperformed in a cyclic fashion with a different monomer or othercomponent being added in each round of synthesis. Some methods areperformed by successively fractionating an initial pool. For example, afirst round of synthesis is performed on all supports. The supports arethen divided into two pools and separate synthesis reactions areperformed on each pool. The two pools are then further divided, eachinto a further two pools and so forth. Other methods employ bothsplitting and repooling. For example, after an initial round ofsynthesis, a pool of compounds is split into two for separate synthesesin a second round. Thereafter, aliquots from the separate pools arerecombined for a third round of synthesis. Split and pool methods resultin a pool of mixed compounds. These methods are particularly amenablefor tagging as described in more detail below. The size of librariesgenerated by such methods can vary from 2 different compounds to 10⁶, or10¹⁰, or any range there between.

Preparation of encoded libraries is described in a variety ofpublications including Needels, et al., Proc. Natl. Acad. Sci. U.S.A.,90:10700 (1993); Ni, et al., J. Med. Chem., 39:1601 (1996), WO 95/12608,WO 93/06121, WO 94/08051, WO 95/35503, and WO 95/30642 (each of which isincorporated herein by reference in its entirety for all purposes).Methods for synthesizing encoded libraries typically involve a randomcombinatorial approach and the chemical and/or enzymatic assembly ofmonomer units. For example, the method typically includes steps of: (a)apportioning a plurality of solid supports among a plurality of reactionvessels; (b) coupling to the supports in each reaction vessel a firstmonomer and a first tag using different first monomer and tagcombinations in each different reaction vessel; (c) pooling thesupports; (d) apportioning the supports among a plurality of reactionvessels; (e) coupling to the first monomer a second monomer and couplingto either the solid support or to the first tag a second tag usingdifferent second monomer and second tag combinations in each differentreaction vessel; and optionally repeating the coupling and apportioningsteps with different tags and different monomers one to twenty or moretimes. The monomer set can be expanded or contracted from step to step;or the monomer set could be changed completely for the next step (e.g.,amino acids in one step, nucleosides in another step, carbohydrates inanother step). A monomer unit for peptide synthesis, for example, caninclude single amino acids or larger peptide units, or both.

Compounds synthesizable by such methods include polypeptides, beta-turnmimetics, polysaccharides, phospholipids, hormones, prostaglandins,steroids, aromatic compounds, heterocyclic compounds, benzodiazepines,oligomeric N-substituted glycines, and oligocarbamates. Preparedcombinatorial libraries are also available from commercial sources(e.g., ChemRx, South San Francisco, Calif.).

Combinatorial libraries and other compounds are initially screened forsuitability by determining their capacity to bind to α2β1, α6β1, or αvβ1integrins, or to laminin. The additional screening procedures describedabove can also be used.

Compounds of Formula Ia and Ib are useful in methods for suppressing Aβinduced inhibition of LTP:

including stereoisomeric forms thereof, or mixtures of stereoisomericforms thereof, or pharmaceutically acceptable salt forms thereof,wherein:

X₁ and X₃ are independently selected from nitrogen or carbon;

R¹ is selected from:

wherein the above heterocycles are optionally substituted with 0-2substituents selected from the group consisting of: NH₂, halogen, NO₂,CN, CF₃, C₁-C₄ alkoxy, C₁-C₆ alkyl, and C₃-C₇ cycloalkyl;U is selected from —(CH₂)_(n)—, —(CH₂)_(t)Q(CH₂)_(m)— and —C(═O)

(CH₂)₁₋₁—, wherein one of the methylene groups is optionally substitutedwith R⁷; Q is selected from 1,2-phenylene, 1,3-phenylene,2,3-pyridinylene, 3,4-pyridinylene, and 2,4-pyridinylene;

R⁶ is selected from: H, C1-C4 alkyl, and benzyl;R7 is selected from: C₁-C₆ alkyl, C₃-C₇ cycloalkyl,

C₄-C₁₁ cycloalkylalkyl, aryl, aryl(C₁-C₆ alkyl), heteroaryl, andheteroaryl(C₁-C₆ alkyl);

R¹⁰ is selected from: H, halogen, CO₂R¹⁷, CONR¹⁷R²⁰, C₁-C₆ alkylsubstituted with 0-1 R¹⁵ or 0-1 R²¹, C₁-C₄ alkoxy substituted with 0-1R²¹, C₃-C₇ cycloalkyl substituted with 0-1 R¹⁵ or 0-1 R²¹, C₄-C₁₁cycloalkylalkyl substituted with 0-1 R¹⁵ or 0-1 R²¹, and aryl(C₁-C₆alkyl)-substituted with 0-1 R¹⁵ or 0-2 R¹¹ or 0-1 R²¹;R¹¹ is selected from: H, halogen, CF₃, CN, NO₂, hydroxy, NR²R³, C₁-C₄alkyl substituted with 0-1 R²¹, C₁-C₄ alkoxy substituted with 0-1 R²¹,aryl substituted with 0-1 R²¹, aryl(C₁-C₆ alkyl)-substituted with 0-1R²¹, (C₁-C₄ alkoxy)carbonyl substituted with 0-1 R²¹, (C₁-C₄alkyl)carbonyl substituted with 0-1 R²¹, C₁-C₄ alkylsulfonyl substitutedwith 0-1 R²¹, and C₁-C₄ alky-laminosulfonyl substituted with 0-1 R²¹;

W is —C(═O)—N(R¹³)—; X is —CH(R¹⁴)—CH(R¹⁵)—;

R¹³ is selected from H and CH₃;R¹⁴ is selected from: H, C₁-C₁₀ alkyl, aryl, and heteroaryl, whereinsaid aryl or heteroaryl groups are optionally substituted with 0-3substituents selected from: C₁-C₄ alkyl, C₁-C₄ alkoxy, aryl, halo,cyano, amino, CF₃, and NO₂;R¹⁵ is selected from H and R¹⁶;

Y is —COR¹⁹;

R¹⁶ is selected from:

—NH(R²⁰)—C(═O)—R¹⁷,

—N(R²⁰)—C(═O)—R¹⁷,

—N(R²⁰)—C(═O)—NH—R¹⁷,

—N(R²⁰)SO₂—R¹⁷, and

—N(R²⁰)SO₂—N(R²⁰)R¹⁷,

R¹⁷ is selected from: C₁-C₁₀ alkyl, C₃-C₁₁ cycloalkyl, aryl(C₁-C₆alkyl)-, (C₁-C₆ alkyl)aryl, heteroaryl (C₁-C₆ alkyl)-, (C₁-C₆alkyl)heteroaryl, biaryl(C₁-C₆ alkyl)-, heteroaryl, or aryl, whereinsaid aryl or heteroaryl groups are optionally substituted with 0-3substituents selected from the group consisting of: C₁-C₄ alkyl, C₁-C₄alkoxy, aryl, heteroaryl, halo, cyano, amino, CF₃, and NO₂;

R¹⁹ is —O—(CH₂)_(k)N⁺(R²²)(R²³)(R²⁴)Z⁻;

Z⁻ is a pharmaceutically acceptable anion selected from halide,bisulfate, sulfate, hydrogenphosphate, phosphate, toluenesulfonate,methanesulfonate, ethanesulfonate, acetate, trifluoroacetate, citrate,oxalate, succinate, and malonate;

R²², R²³, and R²⁴ are independently selected from H, C₁-C₄ alkyl, andC₄-C₁₁ cycloalkylalkyl;

alternatively R²² and R²³ can be taken together to form a 5-7 memberedheterocyclic ring system containing 1-2 heteroatoms selected from N, Oand S, and R²⁴ is defined as above or R²², R²³, and R²⁴ can be takentogether to form a heterobicyclic ring system containing 1-2 heteroatomsselected from N, O and S;

R²⁰ is selected from H and CH₃;

R²¹ is selected from COOH and NR⁶ ₂;

k is 2;m is selected from 0 and 1;n is 1-4; andt is selected from 0 and 1.

Examples of compounds of Formula Ia include, but are not limited to,compounds of Formula II:

; wherein R¹⁹ is chosen from —H, —CH₃, and —CH₂CH₂N⁺(CH₃)₃. In anembodiment, R19 is —H (the compound of Formula II is SM256).

Additional compounds useful in methods for suppressing Aβ inducedinhibition of LTP include compounds disclosed in U.S. Pat. No.6,214,834. That patent discloses use of SM256 (Formula II), and othercompounds, to antagonize α_(v)β₃. Accordingly, α_(v)β₃ antagonists maybe screened to identify compounds that bind to integrin subunit αv underconditions such that the one or more agents suppress amyloid-mediatedinhibition of LTP. Exemplary α_(v)β₃ antagonists that may be so screenedinclude, but are not limited to, α_(v)β₃ antagonists disclosed in U.S.Pat. No. 6,214,834.

C. Gene Suppression Agents

Agents that suppress gene expression can be used to suppress theexpression of genes encoding integrin subunits β1, α2, α6 or αv.Antisense agents can also be used to suppress expression of certainligands thereto, such as laminin. Suppression of laminin expression canachieve similar effects to treatment with antibodies against laminin.Administration of the antisense reagents of the invention to a targetcell or patient results in reduced activity of one of the above integringenes or its ligand. For general methods relating to antisensepolynucleotides, see, e.g., Antisense RNA and DNA, (1988), D. A. Melton,Ed., Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.); Dagle etal., Nucleic Acids Research, 19:1805 (1991); Uhlmann et al., Chem.Reviews, 90:543-584 (1990). Ribozymes are another antisense agent thatcan suppress gene expression.

Antisense oligonucleotides can cause suppression by binding to, andinterfering with the translation of sense mRNA, rendering mRNAsusceptible to nuclease digestion, interfering with transcription,interfering with the processing or localization of RNA precursors,repressing the transcription of mRNA, or acting through some othermechanism. The particular mechanism by which the antisense moleculereduces expression is not critical.

Typically antisense polynucleotides comprise an antisense sequence of atleast 7 to 10 to typically 20 or more nucleotides that specificallyhybridize to a sequence from an mRNA of a gene. Some antisensepolynucleotides are from about 10 to about 50 nucleotides in length orfrom about 14 to about 35 nucleotides in length. Some antisensepolynucleotides are polynucleotides of less than about 100 nucleotidesor less than about 200 nucleotides. In general, the antisensepolynucleotide should be long enough to form a stable duplex, but shortenough, depending on the mode of delivery, to administer in vivo, ifdesired. The minimum length of a polynucleotide required for specifichybridization to a target sequence depends on several factors, such asthe G/C content, the positioning of mismatched bases (if any), theoverall differences of the sequence relative to the population of targetpolynucleotides, and the chemical nature of the polynucleotide (e.g.,methylphosphonate backbone, peptide nucleic acid, phosphorothioate),among other factors.

Suitable conditions for hybridizing complementary nucleic acid moleculesare well known to those of skill in the art. For example, hybridizationunder typical high stringency conditions may be performed in a mixturecontaining 5×SSPE, 5×Denhart solution, 0.5% SDS (w/v), and 100 μg/mlsalmon sperm DNA. The DNA is allowed to hybridize for a specified periodof time at about 68° C. The hybridized DNA, which is typically bound toa membrane or filter, is then washed 2 times for 10 minutes, in 2×SSPE,0.1% SDS (w/v) at room temperature. The membrane (or filter) is thenimmersed in a solution of 1×SSPE, 0.1% SDS (w/v) for 15 minutes at 68°C., and finally in a solution of 1×SSPE, 0.1% SDS (w/v) for 15 minutesat 68° C.

To ensure specific hybridization, the antisense sequence is at leastsubstantially complementary to the target mRNA or gene encoding thesame. Some antisense sequences are exactly complementary to theirintended target sequence. The antisense polynucleotides can alsoinclude, however, nucleotide substitutions, additions, deletions,transitions, transpositions, or modifications, or other nucleic acidsequences or non-nucleic acid moieties so long as specific binding tothe relevant target sequence corresponding to the RNA or its gene isretained as a functional property of the polynucleotide.

Some antisense sequences are complementary to relatively accessiblesequences of mRNA (e.g., relatively devoid of secondary structure). Thiscan be determined by analyzing predicted RNA secondary structures using,for example, the MFOLD program (Genetics Computer Group, Madison Wis.)and testing in vitro or in vivo as is known in the art. Another usefulmethod for identifying effective antisense compositions usescombinatorial arrays of oligonucleotides (see, e.g., Milner et al.,Nature Biotechnology, 15:537 (1997).

One technique to inhibit gene expression involves the introduction ofdouble-stranded RNA, also referred to as inhibitory RNA (RNAi), into acell. The RNAi comprises two complementary strands of RNA (a sensestrand and an antisense strand) annealed to each other to form a doublestranded RNA molecule. The RNAi is typically derived from an exon orcoding sequence of the gene that is being targeted for inhibition. TheRNAi results in the destruction of mRNA complementary to the sequence ofthe RNAi molecule. Examples of RNAi and their use in living organismsare described, for example, by Fire et al., Nature, 391:806-811 (1998);Nykänen et al., Cell, 107:309-321 (2001); and in WO 01/29058, WO01/75164, and WO 99/32619. In some methods the RNAi is between about 100bp and 1000 bp, for example, about 100, 200, 300, 400, 500, 600, 700,800, 900, 1000, or more base pairs. In some methods the RNAi is derivedfrom an exon. In other methods, the RNAi is derived from an intron orsignaling sequence.

In some methods, antisense polynucleotides have sequences in addition tothe antisense sequence, including promoters and other regulatorysequences that result in expression of an antisense sequence. Providedthat the promoter and, preferably termination and polyadenylationsignals, are properly positioned, the strand of the inserted sequencecorresponding to the noncoding strand is transcribed and acts as anantisense oligonucleotide. In some methods, the polynucleotide consistsessentially of, or is, the antisense sequence. The antisense nucleicacids (DNA, RNA, modified, analogues, and the like) can be made usingany suitable method for producing a nucleic acid, such as the chemicalsynthesis and recombinant methods disclosed herein. For example,antisense RNA molecules can be prepared by de novo chemical synthesis orby cloning.

Zinc finger proteins can be used as an alternative or in addition toantisense polynucleotides to suppress the expression of the genesencoding the β1, α2, α6 or αv integrin subunits. Zinc finger proteinscan also be used to suppress the expression of certain ligands of theseintegrin subunits, such as laminin. Zinc finger proteins can also beused to activate or enhance the expression of other ligands, such asfibronectin, that can themselves be used as agents in the presentmethods. Zinc finger proteins can be engineered or selected to bind toany desired target site within a target gene. In some methods, thetarget site is within a promoter or enhancer. In other methods, thetarget site is within the structural gene. In some methods, the zincfinger protein is linked to a transcriptional repressor, such as theKRAB repression domain from the human KOX-1 protein (Thiesen et al., NewBiologist, 2, 363-374 (1990); Margolin et al., Proc. Natl. Acad. Sci.U.S.A., 91, 4509-4513 (1994)); Pengue et al., Nucl. Acids Res.,22:2908-2914 (1994); Witzgall et al., Proc. Natl. Acad. Sci. U.S.A., 91,4514-4518 (1994). Preferred domains for achieving activation include theHSV VP16 activation domain (see, e.g., Hagmann et al., J. Virol.,71:5952-5962 (1997)) nuclear hormone receptors (see, e.g., Torchia etal., Curr. Opin. Cell. Biol., 10:373-383 (1998)); the p65 subunit ofnuclear factor kappa B (Bitko & Barik, J. Virol., 72:5610-5618 (1998)and Doyle & Hunt, Neuroreport, 8:2937-2942 (1997)); Liu et al., CancerGene Ther., 5:3-28 (1998)), or artificial chimeric functional domainssuch as VP64 (Seifpal et al., EMBO J., 11:4961-4968 (1992)). Methods forselecting target sites suitable for targeting by zinc finger proteins,and methods for designing zinc finger proteins to bind to selectedtarget sites are described in WO 00/00388. Methods for selecting zincfinger proteins to bind to a target using phage display are described byEP 95908614A. Methods for using zinc finger proteins to regulateendogenous genes are described in WO 00/00409. Zinc finger proteins canbe administered either as proteins or in the form of nucleic acidsencoding zinc fingers and having appropriate regulatory sequences.

D. Nucleic Acids Encoding Therapeutic Agents

Antibody or other peptide reagents can be administered in the form ofnucleic acids encoding antibody chains or peptides. Such nucleic acidsare typically linked to regulatory elements, such as a promoter andenhancer, that allow expression of the DNA segment in the intendedtarget cells of a patient. Promoter and enhancer elements from light orheavy chain immunoglobulin genes or the cytomegalovirus (CMV) majorintermediate early promoter and enhancer are suitable to directexpression. In some methods promoters that cause expression in the brainare used. Promoters such as platlet-derived growth factor (PDGF), prion,or the neural enolase promoter are suitable.

The linked regulatory elements and coding sequences are often clonedinto a vector. For administration of double-chain antibodies, the twochains can be cloned in the same or separate vectors.

A number of viral vector systems are available including retroviralsystems (see, e.g., Lawrie and Tumin, Curr. Opin. Genet Develop.,2:102-109 (1993)); adenoviral vectors (see, e.g., Bett et al., J.Virol., 67:5911 (1993)); adeno-associated virus vectors (see, e.g., Zhouet al., J. Exp. Med., 179:1867-75 (1994)), viral vectors from the poxfamily including vaccinia virus and the avian pox viruses, viral vectorsfrom the alpha virus genus such as those derived from Sindbis andSemliki Forest Viruses (see, e.g., Dubensky et al., J. Virol., 70:508-19(1996)), Venezuelan equine encephalitis virus (see U.S. Pat. No.5,643,576), rhabdoviruses, such as vesicular stomatitis virus (see WO96/34625), and papillomaviruses (Ohe et al., Human Gene Therapy,6:325-33 (1995); Woo et al., WO 94/12629; and Xiao & Brandsma, NucleicAcids. Res., 24:2630-22 (1996)).

DNA can be packaged into liposomes. Suitable lipids and related analogsare described by U.S. Pat. Nos. 5,208,036, 5,264,618, 5,279,833, and5,283,185. Vectors and DNA encoding an immunogen can also be adsorbed toor associated with particulate carriers, examples of which includepolymethyl methacrylate polymers, polylactides, andpoly(lactide-co-glycolides).

Gene therapy vectors or naked DNA can be delivered in vivo byadministration to an individual patient, typically by systemicadministration (e.g., intravenous, intraperitoneal, nasal, gastric,intradermal, intramuscular, intrathecal, subdermal, or intracranialinfusion) or topical application (see, e.g., U.S. Pat. No. 5,399,346).Such vectors can further include facilitating agents such as bupivacine(U.S. Pat. No. 5,593,970). DNA can also be administered using a genegun. See Xiao & Brandsma, supra. The DNA is precipitated onto thesurface of microscopic metal beads. The microprojectiles are acceleratedwith a shock wave or expanding helium gas, and penetrate tissues to adepth of several cell layers. For example, the Accel™ Gene DeliveryDevice manufactured by Agacetus, Inc., Middleton, Wis. is suitable.Alternatively, naked DNA can pass through skin into the blood streamsimply by spotting the DNA onto skin with chemical or mechanicalirritation (see WO 95/05853).

In a further variation, nucleic acids can be delivered to cells ex vivo,such as cells explanted from an individual patient (e.g., lymphocytes,bone marrow aspirates, tissue biopsy) or universal donor hematopoieticstem cells, followed by reimplantation of the cells into a patient,usually after selection for cells that have incorporated the vector.

E. Identification of Agents that Suppress Aβ Mediated Inhibition of LTP

Small molecule agents that bind to integrin subunit αv may beadministered under conditions such that the one or more agents suppressamyloid-mediated inhibition of LTP. Suitable small molecule agents areidentified, for example, by a method comprising an integrin subunit αvbinding assay and an amyloid-mediated inhibition of LTP suppressionassay, or by a method comprising an amyloid-mediated inhibition of LTPsuppression assay but not comprising an integrin subunit αv bindingassay.

An integrin subunit αv binding assay is, for example, any assay thatidentifies specific binding of an agent to integrin subunit αv, eitheras a monomer or a dimer. Exemplary assays detect binding directly, suchas by use of a labeled agent that is bound to integrin subunit αv, whichmay be immobilized, such as by direct or indirect attachment to asubstrate. Further exemplary assays detect binding indirectly. In anembodiment a competitive binding assay is used. Competitive binding maybe performed, for example, using another integrin subunit αv-bindingagent, such as one disclosed herein or known in the art, or a bindingagent previously identified by an assay disclosed herein. Suitablebinding agents for use in an integrin subunit αv binding assay include,but are not limited to, fibronectin or superfibronectin, a monoclonal orpolyclonal antibody, an antibody that recognizes the same epitope as anantibody chosen from 18C7, 20A9, and 17E6, and antibody chosen from18C7, 20A9, and 17E6, an agent that competes for binding to the integrinsubunit αv with an antibody chosen from 18C7, 20A9, and 17E6, and acompound of Formula 1, such as SM256.

An amyloid-mediated inhibition of LTP suppression assay includes, but isnot limited to, assays using a system in which LTP is experimentallyinduced. Suitable systems may be in vivo or in vitro, such as in brainslices comprising the hippocampal region or a subregion of thehippocampus. Exemplary assays are described in examples 10-13.

In those examples LTP is induced by HFS or pharmacological stimulation.LTP is inhibited by Aβ peptide, added to the system before, concurrentlywith, or after administration of HFS or pharmacological stimulation.Suppression of amyloid-mediated inhibition of LTP by a candidate agentis then assayed by comparing the inhibition of LTP by Aβ peptide in thepresence and absence of the candidate agent. The degree of suppressionis measured in relation to the amplitude of field excitatorypostsynaptic potentials (EPSPs) observed following HFS orpharmacological stimulation of a control system, which can either be thesystem following induction of LTP in the absence of Aβ peptide and/orthe system following inhibition of LTP by Aβ peptide.

IV. Secondary Agents

The present invention is further directed to the co-administration ofone or more agents and one or more secondary agents. For example,suitable secondary agents include, but are not limited to, a secondaryagent selected from an inhibitor of Aβ production, an inhibitor of Aβdeposition, a mediator of Aβ clearance, a mediator of amyloid plaqueclearance, an inhibitor of Aβ neurotoxicity, an inhibitor of Aβaggregation, a mediator of Aβ disaggregation, and an antibody to Aβ, andany combination thereof. Suitable inhibitors of Aβ production include,but are not limited to, gamma secretase inhibitors and beta secretaseinhibitors.

Exemplary gamma secretase inhibitors include, but are not limited to,gamma secretase inhibitors such as those disclosed in U.S. Pat. Nos.6,992,081, 6,982,264, 6,962,934, and 6,610,493, and U.S. PatentApplication Publications Nos. 20060287306, 20060154926, 20050159460,20020016320, and 20030148392.

Exemplary beta secretase inhibitors include, but are not limited to,beta secretase inhibitors such as those disclosed in U.S. Pat. Nos.7,115,410, 7,109,017, 7,067,271, 6,864,240, 6,852,482, 6,627,739,6,321,163, 6,221,645, 5,942,400, and 5,744,346, and U.S. PatentApplication Publications Nos. 20050196839, 20050182138, 20050177888,20050170489, 20050164327, 20050164294, and 200402655965.

Exemplary antibodies to Aβ include, but are not limited to, antibodiesto Aβ such as those disclosed in U.S. Pat. Nos. 7,014,855, 6,982,084,6,972,127, 6,962,707, 6,946,135, 6,913,745, 6,905,686, 6,890,535,6,875,434, 6,866,850, 6,866,849, 6,818,218, 6,808,712, 6,787,637,6,787,523, 6,787,144, 6,787,143, 6,787,140, 6,787,139, 6,787,138,6,761,888, 6,750,324, 6,743,427, and 6,710,226.

V. Long Term Potentiation

Long Term Potentiation occurs naturally in vivo or vitro, and may beexperimentally induced in an in vitro or in vivo model system. Certainmethods disclosed herein contemplate experimental induction of LTP,which can be inhibited by administration or exposure of the experimentalsystem to Aβ peptide. In those methods, agents are used toexperimentally suppress that inhibition of LTP by Aβ peptide. Naturallyoccurring LTP is inhibited by Aβ peptide in the course of development ofvarious amyloidogenic disease states. An agent disclosed herein may beadministered to a patient, for example, as a pharmaceutical preparation,to treat and/or prevent inhibition of LTP by Aβ peptide in vivo and/orto treat and/or prevent the disease state.

LTP may be experimentally induced by delivery of HFS or bypharmacological methods. For an experimental model of LTP inhibition, aneural circuit exhibiting LTP in response to experimental manipulationis provided. That can be done with an organism chosen from an animal,such as a mammal, such as a rodent or primate, such as a mouse or rat.Techniques are known in the art for experimentally inducing LTP inmammalian brain slices, such as primate or rodent brain slices, culturedin vitro, or in the brain of a mammal in vivo.

LTP strength can be quantified by the magnitude of EPSP elevationobserved relative to baseline (in the absence of induction) at adesignated time following induction. That magnitude may be expressed asa percentage relative to baseline, such as 150%. LTP inhibition,observed following administration of Aβ peptide, results in a reductionin the magnitude of EPSP elevation relative to baseline.

For example, Aβ peptide inhibits LTP completely, to the point that theEPSP observed following HFS is not statistically different thanbaseline. When that inhibition is suppressed, LTP can be observed evenin the presence of Aβ. That suppression can be quantified relative tothe magnitude of EPSP observed following induction of LTP in the absenceof Aβ. For example, suppression may be complete, so that the magnitudeof EPSP observed across a data set following induction of LTP in thepresence of Aβ and an αv binding agent, is statisticallyindistinguishable from the magnitude of EPSP observed followinginduction of LTP in the absence of Aβ. In other embodiments, themagnitude of EPSP observed across a data set following induction of LTPthe presence of Aβ and an αv binding agent is, for example, greater that25%, greater than 50%, greater than 75%, greater than 85%, greater than90%, or greater than 95% of the magnitude of EPSP observed followinginduction of LTP in the absence of Aβ.

VI. Patients Amenable to Treatment

The present methods are useful for prophylactic or therapeutic treatmentof diseases or disorders charactarized by a loss of memory or apotential for loss of memory, including diseases or disorderscharacterized by progressive memory loss. Exemplary diseases ordisorders include, but not limited to, amyloidogenic diseases andconditions that are characterized by the presence of deposits of amyloidproteins, such as amylin or Aβ peptide. Such diseases includeAlzheimer's disease, Down's syndrome and cognitive impairment, type IIdiabetes, Parkinson's disease, diffuse lewy body disease, amyloidosessuch as hereditary or systemic amyloidoses, and diseases caused all orin part by prion infection.

Patients amenable to treatment include individuals at risk of diseasebut not showing symptoms, as well as patients presently showingsymptoms. In the case of Alzheimer's disease, virtually anyone is atrisk of suffering from Alzheimer's disease if he or she lives longenough. The present methods are especially useful for individuals whohave a known genetic risk of Alzheimer's disease. Such individualsinclude those having relatives who have experienced this disease, andthose whose risk is determined by analysis of genetic or biochemicalmarkers. Genetic markers of risk toward Alzheimer's disease includemutations in the APP gene, for example mutations at position 717 andpositions 670 and 671 referred to as the Hardy and Swedish mutationsrespectively (see Hardy, TINS, supra). Other markers of risk aremutations in the presenilin genes, PS1 and PS2, and ApoE4, familyhistory of AD, hypercholesterolemia, or arteriosclerosis. Individualspresently suffering from Alzheimer's disease can be recognized fromcharacteristic dementia, as well as the presence of the risk factorsdescribed above. In addition, a number of diagnostic tests are availablefor identifying individuals who have AD. These include measurement ofcerebrospinal fluid (CSF) tau and Aβ42 levels. Elevated tau anddecreased Aβ42 levels signify the presence of AD. Individuals sufferingfrom Alzheimer's disease can also be diagnosed by ADRDA criteria. Inasymptomatic patients, treatment can begin at any age (e.g., about 10,about 20, about 30). Usually, however, it is not necessary to begintreatment until a patient reaches about 40, about 50, about 60, about70, about 80 or about 90. Treatment typically entails multiple dosagesover a period of time. In the case of Down's syndrome patients,treatment can begin prenatally by administering therapeutic agents tothe mother; or treatment may begin shortly after birth.

VII. Treatment Regimes

In prophylactic applications, pharmaceutical compositions or medicamentsare administered to a patient susceptible to, or otherwise at risk ofdeveloping an amyloidogenic disease, in an amount sufficient toeliminate or reduce the risk, lessen the severity, or delay the onset ofthe disease, including biochemical, histological and/or behavioralsymptoms of the disease, its complications and intermediate pathologicalphenotypes presenting during development of the disease.

In therapeutic applications, compositions or medicaments areadministered to a patient suspected of, or already suffering from such adisease in an amount sufficient to cure, or at least partially arrest,the symptoms of the disease (biochemical, histological, and/orbehavioral), including its complications and intermediate pathologicalsymptoms. An amount adequate to accomplish therapeutic or prophylactictreatment is defined as a therapeutically- or prophylactically-effectivedose. In therapeutic regimes, the agent is usually administered atintervals until symptoms of the disease disappear or significantlydecrease. Optionally administration can be continued to preventrecurrence. In prophylactic regimes, agents are also usuallyadministered at intervals, in some instances for the rest of a patient'slife. Treatment can be monitored by assaying levels of administeredagent, or by monitoring the response of the patient. The response can bemonitored by ADRDA criteria and imaging of plaques in the brain of thepatient (see WO 00/14810).

Effective doses of the compositions of the present invention, for thetreatment of the above-described conditions vary depending upon manydifferent factors, including means of administration, target site,physiological state of the patient, whether the patient is human or ananimal, other medications administered, and whether treatment isprophylactic or therapeutic. Usually, the patient is a human; nonhumanmammals, including transgenic mammals, can also be treated. Treatmentdosages are typically titrated to optimize safety and efficacy.

Dosages of antibodies, peptides, and small molecules range from about0.0001 to about 100 mg/kg, and more usually about 0.01 to about 20mg/kg, of the host body weight. For example, dosages can be about 1mg/kg body weight or about 20 mg/kg body weight or within the range ofabout 1 to about 10 mg/kg. An exemplary treatment regime entailsadministration once per every two weeks or once a month or once every 3to 6 months. In some methods, two, three, four or more monoclonalantibodies with different binding specificities are administeredsimultaneously, in which case the dosage of each antibody administeredfalls within the ranges indicated. For example, in some methodsantibodies to two or all three of β1 integrin, α2 integrin, and αvintegrin subunits are administered simultaneously. In some methods,antibodies to the α6 integrin subunit are also administered. Antibody isusually administered on multiple occasions. Intervals between singledosages can be weekly, monthly or yearly. Intervals can also beirregular as indicated by measuring blood levels of antibody tointegrins in the patient. In some methods, dosage of antibody isadjusted to achieve a plasma antibody concentration of about 1 to about1000 μg/ml, and in some methods about 25 to about 300 μg/ml.Alternatively, antibody can be administered as a sustained releaseformulation, in which case less frequent administration is required.Dosage and frequency vary depending on the half-life of the antibody inthe patient. In general, human antibodies show the longest half life,followed by humanized antibodies, chimeric antibodies, and nonhumanantibodies. The dosage and frequency of administration can varydepending on whether the treatment is prophylactic or therapeutic. Inprophylactic applications, a relatively low dosage is administered atrelatively infrequent intervals over a long period of time. Somepatients continue to receive treatment for the rest of their lives. Intherapeutic applications, a relatively high dosage at relatively shortintervals is sometimes required until the progression of the disease isreduced or terminated, and preferably until the patient shows partial orcomplete amelioration of the symptoms of the disease. Thereafter, thepatient can be administered a prophylactic regime.

Doses for nucleic acid encoding agents range from about 10 ng to 1 g,about 100 ng to about 100 mg, about 1 μg to about 10 mg, or about 30 toabout 300 μg DNA per patient. Doses for infectious viral vectors mayvary from about 10 to about 100, or about 10³, about 10⁴, about 10⁵,about 10⁶, about 10⁷, about 10⁸, about 10⁹, about 10¹⁰, or more virionsper dose.

Agents of the invention can be administered by parenteral, topical,intravenous, oral, subcutaneous, intrathecal, intraarterial,intracranial, intraperitoneal, intranasal, or intramuscular means forprophylactic and/or therapeutic treatment. In some methods, agents areinjected directly into a particular tissue where deposits haveaccumulated, for example, intracranial injection. In some methods,intramuscular injection or intravenous infusion are employed for theadministration of antibody. In some methods, particular therapeuticantibodies are injected directly into the cranium. In some methods,antibodies are administered as a sustained release composition ordevice, such as a Medipad™ device.

Agents of the invention can optionally be administered in combinationwith other agents that are at least partly effective in the treatment ofamyloidogenic disease. In the case of Alzheimer's disease and Down'ssyndrome, in which amyloid deposits occur in the brain, agents of theinvention can also be administered in conjunction with other agents thatincrease passage of the agents of the invention across the blood-brainbarrier.

Agents of the invention are often administered as compositionscomprising an active therapeutic agent and a variety of otherpharmaceutically acceptable components. See Remington's PharmaceuticalScience (15th ed., Mack Publishing Company, Easton, Pa., 1980). Theparticular formulation employed depends on the intended mode ofadministration and the therapeutic application. The compositions canalso include, depending on the formulation desired,pharmaceutically-acceptable, non-toxic carriers or diluents, which aredefined as vehicles commonly used to formulate pharmaceuticalcompositions for animal or human administration. The diluent is selectedso as not to negatively impact the biological activity of thecombination. Examples of such diluents include, but are not limited to,distilled water, physiological phosphate-buffered saline, Ringer'ssolution, dextrose solution, and Hank's solution. In addition, thepharmaceutical composition or formulation may also include othercarriers, adjuvants, or nontoxic, nontherapeutic, nonimmunogenicstabilizers, and the like.

Pharmaceutical compositions can also include large, slowly metabolizedmacromolecules such as proteins, polysaccharides such as chitosan,polylactic acids, polyglycolic acids, copolymers (such as latexfunctionalized Sepharose™ beads, agarose, cellulose, and the like),polymeric amino acids, amino acid copolymers, and lipid aggregates (suchas oil droplets or liposomes).

For parenteral administration, agents of the invention can beadministered as injectable dosages of a solution or suspension of thesubstance in a physiologically-acceptable diluent with a pharmaceuticalcarrier that can be a sterile liquid such as water, oils, saline,glycerol, or ethanol. Parenteral compositions for human administrationare sterile, substantially isotonic, and made under GMP conditions.Additionally, auxiliary substances, such as wetting or emulsifyingagents, surfactants, pH buffering substances, and the like, can bepresent in compositions. Other components of pharmaceutical compositionsare those of petroleum, animal, vegetable, or synthetic origin, forexample, peanut oil, soybean oil, and mineral oil. In general, glycols,such as propylene glycol or polyethylene glycol, are preferred liquidcarriers, particularly for injectable solutions. Antibodies can beadministered in the form of a depot injection or implant preparationthat can be formulated in such a manner as to permit a sustained releaseof the active ingredient. An exemplary composition comprises monoclonalantibody at 5 mg/mL, formulated in aqueous buffer containing 50 mML-histidine (optional), 150 mM NaCl, adjusted to a suitable pH with HCl.

Typically, compositions are prepared as injectables, either as liquidsolutions or suspensions; solid forms suitable for solution in, orsuspension in, liquid vehicles prior to injection can also be prepared.The preparation also can be emulsified or encapsulated in liposomes ormicroparticles such as polylactide, polyglycolide, or copolymer forenhanced adjuvant effect, as discussed above (see Langer, Science,249:1527-33 (1990) and Hanes et al., Advanced Drug Delivery Reviews,28:97-119 (1997). The agents of this invention can be administered inthe form of a depot injection or implant preparation that can beformulated in such a manner as to permit a sustained or pulsatilerelease of the active ingredient.

Additional formulations suitable for other modes of administrationinclude oral, intranasal, and pulmonary formulations, suppositories, andtransdermal applications. For suppositories, binders and carriersinclude, for example, polyalkylene glycols or triglycerides; suchsuppositories can be formed from mixtures containing the activeingredient in the range of about 0.5% to about 10%, or about 1% to about2%. Oral formulations include, but are not limited to, excipients suchas pharmaceutical grades of mannitol, lactose, starch, magnesiumstearate, sodium saccharine, cellulose, and magnesium carbonate. Thesecompositions typically take the form of solutions, suspensions, tablets,pills, capsules, sustained release formulations or powders and containabout 10% to about 95% of active ingredient, or about 25% to about 70%.

Topical application can result in transdermal or intradermal delivery.Topical administration can be facilitated by co-administration of theagent with cholera toxin or detoxified derivatives or subunits thereofor other similar bacterial toxins (See Glenn et al., Nature, 391:851(1998)). Coadministration can be achieved by using the components as amixture or as linked molecules obtained by chemical crosslinking orexpression as a fusion protein. Alternatively, transdermal delivery canbe achieved using a skin patch or using transferosomes (Paul et al.,Eur. J. Immunol., 25:3521-24 (1995); Cevc et al., Biochem. Biophys.Acta, 1368:201-15 (1998)).

All documents referenced herein are hereby incorporated herein byreference in their entirety.

EXAMPLES Materials and Methods for Examples 1-5

Sources of Antibody

Antibody Source Antigen Ligand blocked MAB1998 Chemicon human α2integrin collagen and laminin MAB1950Z Chemicon human α2 integrincollagen and laminin Gi9 Immunotech human α2 integrin collagen VNR147Gibco or Chemicon human αV integrin fibrinogen and vitronectin MAB1980Chemicon human αV integrin vitronectin IM1603 Immunotech human αVintegrin vitronectin Lia1/2 Immunotech human β1 integrin fibronectinMAB1965 Chemicon human β1 integrin collagen and fibronectin AIIB2Caroline Damsky, human β1 integrin fibronectin UCSF AB19012 Chemiconhuman laminin laminin AB2034 Chemicon mouse laminin laminin

Tissue Culture

Tissue culture plates were coated with polyethyleneimine (PEI) in 150 mMsodium borate, pH 8.5, and incubated overnight at room temperature.Prior to adding cells, the wells were washed with PBS and MinimalEssential Media (MEM with 10% FBS) was added until cells were ready forplating. Human fetal cerebral cortex (E13-E16) was rinsed with Hank'sBalanced Salt Solution (HBSS). Tissue was triturated in 1 mg of DNAse inHBSS. This suspension was filtered through a 100 micron nylon cellstrainer and spun at 250×g for 5 minutes. The cells were resuspended intrypsin and incubated at 37° C. for 20 minutes. Modified MinimalEssential Media (MMEM with 10% FBS and 1 mg of DNase) was added and thecells were resuspended; then collected again by centrifugation. Cellswere resuspended in MMEM containing B27, and plated in washed PEI-coatedplates at 125,000 cells/well in 96 well plates or at 2.5 millioncells/well in 6 well plates. The human cortical cultures (HCC) wereincubated for 3 weeks with biweekly medium exchanges prior to treatment.

Aβ Generation

Aβ was generated by adding double distilled water (ddH₂0) to Aβ to makeup a 1 mM stock. This was aged for 3 days at 37° C., aliquoted, andstored frozen at −20° C. Soluble Aβ was made by adding DMSO to Aβ tomake a 7.5 mM stock, sonicating for 30 minutes, aliquoting, and freezingat −20° C. Neurotoxic Aβ was generated by adding ddH₂O to Aβ,aliquoting, and freezing at −20° C.

Integrin Immunoprecipitations from HCC Lysates

HCC in 6 well plates were labeled with 100 μCi/ml ³⁵S-Methionine inmethionine-free medium overnight. Cells were washed, lysed with 25 mMHepes, pH 7.5, 1% Triton X-100, 0.1% SDS, 150 mM NaCl, 0.5 mM EDTA, 0.5mM EGTA, and passed through a 26 gauge needle three times. Insolublematerial was removed by centrifugation at 15,000 rpm for 15 minutes at4° C. Lysates were pre-cleared on rabbit anti-mouse (RAM) antibodycoupled to protein A beads and immunoprecipitated with integrinsubunit-specific antibodies (Lia1/2 for β1, TS2/7 for α1, Gi9 for α2,P1B5 for α3, AN100226m for α4, Ab0771 for α5, GoH3 for α6, Y9A2 for α9,and VNR147 for αv). Immunoprecipitates were washed 3 times with 1 ml of25 mM Hepes, pH 7.5, 1% Triton X-100 150 mM NaCl, 0.5 mM EDTA, and 0.5mM EGTA. Immunoprecipitated samples were separated on 8% tris-glycinegels (Novex) and fixed; gels were dried, and the ³⁵S-labeled proteins inthe gels were visualized by autoradiography.

Aβ Immunofluorescence

HCC treated with Aβ for 72 hours were fixed with 4% paraformaldehyde,stained with 5 μg/ml anti-Aβ-3D6-biotin, and visualized with 10 μg/mlstreptavidin-FITC (Jackson).

Aβ Neurotoxicity in Human Cortical Neurons

HCC were pretreated with antibodies or ligands for 30 minutes inneuronal medium (MEM) supplemented with glutamine andpenicillin/streptomycin (basal media). One micromolar Aβ in basal mediumwas added for 1 hour. The medium was removed and the HCC were treatedwith antibodies or ligands and 20 μM soluble Aβ in basal medium for 3days. At three days, the toxicity was determined by incubating in 10%alamar blue in basal medium for two hours. Fluorescence levels weremeasured relative to control and Aβ treated wells in triplicate.

Integrin Heterodimer Associations

HCC in 6-well plates in MMEM media supplemented with N-2 (Bottenstein'sN-2 Formulation, e.g., Catalog #17502, Invitrogen Corp., Carlsbad,Calif.) were placed on wet-ice, washed with PBS, lysed with 25 mM Hepes,pH 7.5, 1% Triton X-100, 0.1% SDS, 150 mM NaCl, 0.5 mM EDTA, and 0.5 mMEGTA, and passed through a 26 gauge needle 3 times. Insoluble materialwas removed by centrifugation at 15,000 rpm for 15 minutes at 4° C.Lysates were precleared on protein A beads and β1 integrinimmunoprecipitated using anti-β1 integrin, Lia1/2 (Immunotech), andRAM/protein G beads (Pharmacia). Immunoprecipitates were washed 3 timeswith 1 ml of 25 mM Hepes, pH 7.5, 1% Triton X-100 150 mM NaCl, 0.5 mMEDTA, and 0.5 mM EGTA. Immunoprecipitated samples were separated on4-12% tris-glycine gels (Novex) and Western-blotted with anti-α2integrin (AB 1936 from Chemicon) or with anti-αv integrin, MAB 1960(Chemicon).

Aβ Induction of Paxillin Phosphorylation

Neurotoxic Aβ was added to HCC in 6-well plates in basal mediasupplemented with N-2 for 0 minutes to 24 hours. HCC was placed onwet-ice, washed with PBS, lysed with 25 mM Hepes, pH 7.5, 1% TritonX-100, 0.1% SDS, 150 mM NaCl, 0.5 mM EDTA, and 0.5 mM EGTA, and passedthrough a 26 gauge needle 3 times. Insoluble material was removed bycentrifugation at 15,000 rpm for 15 minutes at 4° C. Lysates wereprecleared on protein A beads and Fak or Pyk2 immunoprecipitated usinganti-Fak (UBI) or anti-Pyk2 antibody (UBI), respectively, and protein Abeads. Immunoprecipitates were washed 3 times with 1 ml of 25 mM Hepes,pH 7.5, 1% Triton X-100 150 mM NaCl, 0.5 mM EDTA, and 0.5 mM EGTA.Immunoprecipitated samples were separated on 8% tris-glycine gels(Novex) and Western blotted with anti-phosphotyrosine (RC20 fromTransduction labs) and with anti-paxillin (Transduction labs).

Example 1 Immunofluorescence Pattern on Human Cortical Neurons

The present examples produce an in vitro tissue culture model of Aβplaques that form on hippocampal and cortical neurons in Alzheimer'sdisease (AD) and exhibit the associated neurotoxicity. The model usesprimary human cortical neuronal cultures to represent the neuronseffected in AD as closely as possible. Addition of Aβ to these culturesresults in a reproducible Aβ meshwork that forms over 1-3 days on theneurons and subsequently causes toxicity in the neurons. Aβ incubated onplates without HCC also stained as a meshwork but consistently showed amore uniform pattern with extensions that were shorter, thinner, andmore linear than those seen on HCC. FIGS. 1A and 1B compare the meshworkin the presence and absence of HCC.

Example 2 β1 Integrin Mediates Aβ Meshwork and Neurotoxicity

Because the meshwork resembled an extracellular matrix, like thoseformed by integrin, it was investigated whether integrin was present inthe HCC; and if so, if integrin facilitated the Aβ meshwork formation onHCC. Gel electrophoresis showed that β1 integrin is expressed in HCC. Itwas also found that β1 integrin blocking antibodies, including MAB1965,could block the Aβ meshwork pattern from forming on HCC (compare FIG. 2A(without antibody) to FIG. 2B (with antibody)). Whether the meshworkpattern was necessary for the toxicity generated by Aβ in these cultureswas also investigated. To test this, HCC were incubated with β1 integrinblocking antibodies (AIIB2 and MAB1965) that had been shown to block theAβ meshwork. These antibodies also blocked Aβ induced toxicity in a dosedependent manner (FIG. 2C). The antibody AIIB2 is a very potent blockerof Aβ toxicity, exhibiting an IC₅₀ of 170 ng/ml or 1 nM. In contrast, acontrol antibody had no effect on toxicity.

Example 3 Agents that Bind to α2 and αv Integrins Inhibit Meshwork andAB-Mediated Neurotoxicity

β1 integrin can pair with several α subunits to form differentheterodimers. It was therefore tested which α integrin subunits werepresent in the HCC. The α2, α3, α4, α5, α6, and αv integrins wereexpressed in HCC. The α1 and α9 integrins were not expressed in HCC.Inhibitory antibodies against all these alpha integrin subunits weretested for their ability to inhibit Aβ meshwork formation and to inhibitits neurotoxicity. Inhibitory antibodies to α2 and αv inhibited Aβmeshwork formation (FIG. 3A). These antibodies also inhibited Aβ'sneurotoxic effect in HCC (FIG. 3B). To show specificity to theseparticular integrins, 2-3 inhibitory antibodies were tested against eachof these integrins and against the other integrin subunits as well. Avery clear specificity to α1, α2, and αv integrins, mediating both themeshwork formation and neurotoxicity, was found (Table 1).

TABLE 1 Aβ meshwork and neurotoxicity inhibition with integrin blockingantibodies and ligands Meshwork Maximal inhibition Antibody: Inhibitionof toxicity (%) β1 integrin: AIIB2 ND 100 1965 Yes 100 Lia1/2 Yes 80TS2/16 (activating) ND 0 α1 integrin: TS2/7 ND 5 1973Z ND 6 α2 integrin:Gi9 Yes 100 1950Z Yes 100 1998 ND 25 α3 integrin: 1952Z ND 10 2056 ND 102057 ND 20 α4 integrin: AN100226m ND 10 α5 integrin: P1D6 ND 5 SAM1 No 5α6 integrin: GoH3 ND 40 α9 integrin: Y9A2 No 0 αv integrin: VNR147 Yes100 1980 Yes 40 IM1603 ND 20 Fibronectin Yes 32 Superfibronectin Yes 100Laminin ND 20 NCAM antibody No?? 0

A weak but reproducible effect of an anti-α6 antibody on toxicity wasobserved. Finally, to confirm that these effects were directed againstthe integrins and not nonspecifically interfering with Aβpolymerization, Aβ toxicity was analyzed side-by-side in human and mousecortical cultures. The antibodies used in these assays do not crossreactwith mouse integrins. The anti-human integrin antibodies could inhibitAβ toxicity in human cultures but not in mouse cultures, suggesting thatthe antibodies were not nonspecifically interacting with Aβ to inhibittoxicity. It was confirmed that α2 and αv were associated with β1integrin in HCC cells by immunoprecipitating HCC lysates with a β1antibody and then blotting the precipitated material with antibodies forα2 and αv. These results indicate that heterodimers of α2β1 and αvβ1 arefunctional mediators of Aβ meshwork formation and neurotoxicity.

Example 4 Fibronectin and Anti-Laminin Antibodies Inhibit AB MeshworkFormation and Neurotoxicity

Other components of the integrin/extracellular meshwork wereinvestigated for involvement in mediating Aβ meshwork formation andneurotoxicity. These other components included the αvβ1 integrinligands, fibronectin, and superfibronectin (multimers of fibronectindomain forming a meshwork), and the α2β1 ligands, collagen and laminin.Laminin has two chains β1 and γI, both of which are elevated inAlzheimer's disease plaques (Murtomaki et al., J. Neur. Res., 32:261-73(1992)). Fibronectin and superfibronectin were capable of inhibiting Aβmeshwork formation and neurotoxicity (Table 1). This result can beexplained by fibronectin competing with Aβ for effects on αvβ1 function.In contrast, an αvβ1 ligand, laminin, was not capable of inhibiting Aβmeshwork or neurotoxicity (Table 1). To determine why an αvβ1 ligand wasprotective, when an αvβ1 ligand was not, anti-laminin antibodies weretested in the meshwork formation and neurotoxicity assay. Two lamininantibodies were highly protective both in Aβ meshwork formation (FIG.5A) and Aβ mediated neurotoxicity (FIG. 5B). The anti-laminin antibody#AB19012 showed an IC₅₀ of less than 1 nM. In contrast, anti-collagenantibodies, had no effect on Aβ meshwork formation and neurotoxicity(FIG. 5C).

Example 5 Aβ Activates Paxillin Tyrosine Phosphorylation, an Early Eventin Integrin Signaling Pathways

Integrin activation by an extracellular matrix ligand leads to theactivation of focal adhesion kinases, such as Fak, and tyrosinephosphorylation of its substrate, paxillin. To determine if Aβ wassimilarly stimulating integrin signaling pathways, the tyrosinephosphorylation pattern of Fak-associated paxillin upon Aβ addition toHCC (FIG. 6A) was analyzed. Consistent activation of Fak-associatedpaxillin tyrosine phosphorylation was not found. However, a consistentincrease in Pyk2-associated paxillin tyrosine phosphorylation subsequentto Aβ stimulation was observed. Pyk2 is also a focal adhesion kinase andmay be mediating an aberrant Aβ/integrin signaling pathway that leads toneurotoxicity (FIG. 6B). The activation of Pyk2-, rather thanFak-associated paxillin tyrosine phosphorylation, may be what causes atoxic response in these conditions. In any case, Aβ activates paxillintyrosine phosphorylation, an early event in integrin signaling pathways,indicating that the Aβ neurotoxic signal may be mediated through directengagement of the α2β1 and αvβ1 integrin signaling pathways.

Example 6 Amylin Two Component Toxicity

Seed or aggregated amylin (1 mM) from CPR, Inc. (641-80, lot NG-0213)was made by adding 200 μl water/mg powder and then aging the solutionfor three days at 37° C. Soluble amylin (5 mM) was prepared by adding 40μl DMSO/mg powder and sonicating the mixture for 30 minutes in a waterbath. Both stock solutions were aliquoted and frozen until ready foruse. Soluble amylin stock was diluted to 20 μM in culture medium justprior to use and filtered through an Amicon 30 filter that had beenpre-washed with water. Filtered material was then diluted to itsappropriate concentration.

Human cortical neurons (at 125,000 cells/96 well) were treated for 1hour with seed amylin at 5 μM, 100 μ1/well. Cells were aspirated andsoluble amylin was added back at 5 μM per 100 μl/well. For compoundstudies, 50 μl of 2× compound was added before adding the solubleamylin.

FIG. 6 demonstrates toxicity after 1 day when the human cortical neuronswere seeded for 1 hour followed by aspiration and treatment with solubleamylin. Integrin antibodies were added to the cells in the presence ofthe seed and soluble amylin to inhibit toxicity. FIG. 7 demonstratesthat some integrin antibodies, namely 2034 anti-laminin, 1965 anti-β1integrin, 1958 anti-αv (VNR) and 1950 anti-α2, protected the cellsagainst the toxicity of the amylin two components. FIG. 8 demonstratesthat amylin two component toxicity is further inhibited by additionalintegrin antibodies including anti-αvβ3 and anti-αv; and cytochalasin D.

Materials and Methods for Examples 7-11 Preparation of Slices

All experiments were carried out on transverse slices of the rathippocampus (males, age 3-4 weeks, weight 40-80 g) or mice (males, age3-4 months). The brains were rapidly removed after decapitation andplaced in cold oxygenated (95% O₂/5% CO₂) media. Slices were cut at athickness of 350 μm using an Intracell Plus 1000 and placed in a storagecontainer containing oxygenated medium at room temperature (20-22° C.)for 1 hr. The slices were then transferred to a recording chamber forsubmerged slices and continuously superfused at a rate of 5-6 ml/min at30-32° C. The control media contained (in mM): NaCl, 120; KCl 2.5,NaH₂P04, 1.25; NaHC0₃ 26; MgSO₄, 2.0; CaCl₂, 2.0; D-glucose 10. Allsolutions contained 100 μM picrotoxin (Sigma) to block GABA_(A)-mediatedactivity.

In Vitro Electrophysiological Techniques

Standard electrophysiological techniques were used to record fieldpotentials. Presynaptic stimulation was applied to the medial perforantpathway of the dentate gyrus using a bipolar insulated tungsten wireelectrode, and field excitatory postsynaptic potentials (EPSPs) wererecorded at a control test frequency of 0.033 Hz from the middleone-third of the molecular layer of the dentate gyrus with a glassmicroelectrode. The inner blade of the dentate gyrus was used in allstudies. In each experiment, an input-output curve (afferent stimulusintensity versus EPSP amplitude) was plotted at the test frequency. Forall experiments, the amplitude of the test EPSP was adjusted toone-third of maximum (˜1.2 mV). LTP was evoked by 8 trains of highfrequency stimulation (HFS), each of 8 stimuli at 200 Hz, inter-traininterval 2s, with the stimulation voltage increased during the HFS so asto evoke an initial EPSP of the train of double the normal test EPSPamplitude. Control (vehicle alone) and experimental levels of LTP weremeasured on slices prepared from the same hippocampus. Recordings wereanalysed using p-CLAMP (Axon Instruments, CA, USA). The values reportedherein were the means ±S.E.M. for n slices. Two-tailed Student's t-testwas used for statistical comparison.

In Vivo Electrophysiology

Experiments were carried out on urethane (ethyl carbamate, 1.5 gm/kgi.p.) anaesthetized male Wistar rats (250-300 g). Body temperature wasmaintained at 37-37.3° C. The animal care and experimental protocol wasapproved by the Department of Health, Republic of Ireland.

Electrodes were made and implanted as described previously (Klyubin etal, 2004, 2005). Briefly, twisted-wire bipolar electrodes wereconstructed from Teflon-coated tungsten wires (62.5 μm inner corediameter, 75 μm external diameter). Single pathway recordings of fieldexcitatory postsynaptic potentials (EPSPs) were made from the stratumradiatum in the CA1 area of the right hippocampal hemisphere in responseto stimulation of the ipsilateral Schaffer collateral-commissuralpathway. Electrode implantation sites were identified using stereotaxiccoordinates relative to bregma, with the recording site located about3.4 mm posterior to bregma and about 2.5 mm right of midline, and thestimulating electrode located about 4.2 mm posterior to bregma and about3.8 right of midline. The optimal depth of the wire electrodes in thestratum radiatum of the CA1 region of the dorsal hippocampus wasdetermined using electrophysiological criteria and verified post mortem.Test EPSPs were evoked at a frequency of 0.033 Hz and at a stimulationintensity adjusted to give an EPSP amplitude of 50% of maximum. The HFSprotocol for inducing LTP consisted of 10 trains of 20 stimuli,inter-stimulus interval 5 ms (200 Hz), inter-train interval 2 sec. Theintensity was increased to give an EPSP of about 75% of maximumamplitude during the HFS.

To inject samples, a stainless-steel guide cannula (22 gauge, 0.7 mmouter diameter, 13 mm length) was implanted above the right lateralventricle (about 1 mm lateral to the midline and about 4 mm below thesurface of the dura) just prior to electrode implantation.Intracerebroventricular (i.c.v.) injections were made via an internalcannula (28 gauge, 0.36 mm outer diameter). Verification of theplacement of the cannula was performed post mortem by checking thespread of ink dye after i.c.v. injection. The values reported hereinwere the means ±S.E.M. for n slices. Two-tailed Student's t-test wasused for statistical comparison.

Agents

Synthetic Aβ (1-42) was obtained from Bachem. For the in vitroexperiments, synthetic Aβ₁₋₄₂ was prepared as a stock solution of 50 μMin ammonium hydroxide (0.1%), stored at −20° C., and then added tophysiological medium immediately prior to each experiment. For the invivo experiments, synthetic Aβ(1-42) (Bachem) was re-suspended inice-cold milliQ water or Teplow. An aliquot was removed and centrifugedat 100,000 g for 3 h, conditions known to pellet fibrils andprotofibrils (Klyubin et al., 2004). After centrifugation, thesupernatant, which had a final concentration of soluble Aβ of 30 or 64μM as determined by amino acid analysis, was stored in small aliquots at−80° C.

The following integrin-αv antibodies (all IgG1 isotype) were used in thestudies: 18C7, 17E6 and 20A9 (all from Calbiochem). The controlantibodies used were 7H10, an IgG2a mouse antibody against human ICAM-1and 27/1, an IgG1 isotype. Other compounds used were echistatin(Source), SM256(3-[1-[3-(N-imidazol-2-ylamino)propyl]indazol-5-ylcarbonylamino]-2(S)-(2,4,6-trimethylbenzenesulfonylamino)propionicacid trifluoroacetate) which was prepared by Elan Pharmaceuticals(recoded as ELN 151993) according to the methods of Van Maes et al,1994, superfibernectin (Sigma) and phalloidin (Calbiochem). In the invivo experiments, SM256 was prepared for i.p administration in asuspension of Tween 80 (Sigma) in saline (15% v/v).

Example 7 Anti-Integrin αv Antibodies Prevent the Aβ-Mediated Inhibitionof LTP in the Dentate Gyrus in Vitro

The induction of LTP by a brief HFS in the dentate gyrus in vitro wasprevented by pre-perfusion of Aβ for 30 min prior to HFS, confirmingprevious studies (Wang et al, 2004a,b, 2005). Thus, LTP in the presenceof Aβ (500 nM), a concentration previously found to cause maximuminhibition of LTP (Wang et al, 2004a) measured 105±3% baseline at 1 hpost-HFS (FIG. 10A) (n=5, P<0.001), that was significantly reducedcompared with control LTP, which measured 152±5% (FIG. 10A).

The effect of perfusing selective antibodies against αv integrinsubunits was investigated on the Aβ-mediated inhibition of LTP. Threedifferent antibodies to αv-containing integrins were investigated,termed 18C7, 20A9 and 17E6. None of the antibodies had any effect onbaseline EPSPs or LTP induction. However, the Aβ-mediated inhibition ofLTP was prevented by perfusion of each of the αv antibodies. FIGS.10A-10C show that all three αv antibodies were effective in preventingthe inhibitory effect of Aβ on LTP compared with interleaved controlexperiments. Thus, LTP measured 144±6%, 137±7, and 153±11% in thepresence of Aβ plus anti-integrin antibodies 18C7, 20A9 and 17E6. Thevalues were not significantly different in comparison to control LTP(n=5 for each experiment, P>0.01). In interleaved slices carried outalongside each antibody experiment, LTP measured 105±3%, 105±6% and103±3% in the presence of Aβ alone, values not significantly differentfrom those of Aβ alone on LTP (n=5 for each experiment, P>0.01).

In contrast, two control antibodies did not significantly prevent theAβ-mediated inhibition of LTP. LTP measured 105±6% in the presence of Aβplus the control antibody, 27/1 (FIG. 11A), and 107±8% in the presenceof Aβ plus the control antibody 7H10 (an isotype control) (FIG. 11B)(n=5, P>0.05).

Example 8 Anti-αv Integrin Antibodies Prevent the Aβ-Mediated Inhibitionof LTP in the CA1 in Vivo

The induction of LTP in CA1 in urethane anaesthetized rats was preventedby i.c.v. injection of soluble fibril-free Aβ 10 min prior to HFS,confirming previous studies (Klyubin et al, 2004). In control vehicleinjected animals, LTP measured 140±5% baseline at 3 h post-HFS (n=6). Inthe presence of soluble fibril-free Aβ (50 pmol in 5 μl, n=5), LTP wasstrongly inhibited, measuring 105±5% (FIG. 12A), which was significantlyreduced compared with control LTP (P<0.001). A selective antibodyagainst αv integrin subunits, 17E6 (27.9 μg in 10 μl), prevented theAβ-mediated inhibition of LTP, which measured 135±8% (n=5, P<0.01compared to vehicle plus Aβ; P>0.05 compared to vehicle plus vehicle).An isotype (IgG1 mouse) control antibody, 27/1 (27.9 μg in 10 μl),failed to affect the Aβ-mediated inhibition of LTP (103±6%, n=6, P>0.05compared to vehicle plus Aβ; P<0.01 compared to vehicle plus vehicle)(FIG. 12B).

Example 9 Small Molecule Non-Peptide Antagonists of αv-ContainingIntegrins Prevent the Aβ-Mediated Inhibition of LTP in the Dentate Gyrusin Vitro and CA1 in Vivo

SM256 is a non-peptide agent that is a potent αv antagonist and inhibitsαv mediated cell adhesion (Van Waes et al, 2000). SM256 (10 μl M) alonedid not inhibit LTP, which measured 148±7%. However, SM256 prevented theAβ-mediated block of LTP, which measured 129±5% (FIG. 13A) (n=5,P<0.01).

Similarly, systemic pre-administration of SM256 abrogated the inhibitionof LTP in the CA1 in vivo caused by i.c.v. injection of soluble,fibril-free Aβ. The dose of SM256 chosen (40 mg in 1.2 ml vehicle, i.p.)had no discernible effect on baseline synaptic transmission or controlLTP (FIG. 12C and data not shown). Soluble Aβ (50 pmol, i.c.v.) injected40 min after SM256 and 10 min before the HFS failed to inhibit LTP,which measured 133±5% (FIG. 12C, n=4; P<0.01 compared to pre-HFSbaseline; P>0.05 compared to peripheral vehicle plus central vehicle,144±9%, n=3) and which was significantly different from the magnitude ofLTP in animals given a peripheral injection of vehicle followed bycentral injection of Aβ (103±10%, n=4, P<0.05).

Example 10 Superfibronectin Prevents the Aβ-Mediated Inhibition of LTPin the Dentate Gyrus in Vitro

Superfibronectin is a ligand for αvβ1 (Morla et al, 1994).Superfibronectin (1 μM) alone did not inhibit LTP, which measured155±2%. However, superfibronectin prevented the Aβ-mediated block of LTPwhich measured 147±6% (FIG. 13B) (n=5, P<0.01).

Example 11 Disintegrins Prevent the Aβ-Mediated Inhibition of LTP in theDentate Gyrus in Vitro

The effect of the disintegrin echistatin was also investigated on theAβ-evoked inhibition of LTP. Disintegrins are small 4-10 kDaRGD-containing cystein rich peptides isolated from snake venom, that areantagonists of integrin, binding to integrins with very high affinityand more potently than the RGD peptide (Gan et al, 1988). Echistatin isone such disintegrin that has been shown to inhibit RGD-dependentintegrin including αv/β3 and α5/β1 (Kumar et al, 1997). Echistatin (50nM) alone did not inhibit LTP, which measured 158±5%. However,echistatin prevented the Aβ-mediated block of LTP, which measured143±6%, n=5, P<0.01 (FIG. 13C).

All publications, patents, and patent applications cited above areincorporated by reference in their entirety for all purposes to the sameextent as if each individual publication or patent application werespecifically and individually indicated to be so incorporated byreference. Although the present invention has been described in somedetail by way of illustration and example for purposes of clarity andunderstanding, it will be apparent that certain changes andmodifications may be practiced within the scope of the appended claims.

1. A method of suppressing amyloid-mediated inhibition of long-termpotentiation (LTP), comprising administering an effective dosage of oneor more agents that bind to integrin subunit αv under conditions suchthat the one or more agents suppress amyloid-mediated inhibition of LTP.2. A method of treating or preventing an amyloidogenic diseasecharacterized by Aβ deposition, comprising administering an effectivedosage of one or more agents that bind to integrin subunit αv underconditions such that the one or more agents suppress amyloid-mediatedinhibition of LTP.
 3. The method of claim 2, wherein the amyloidogenicdisease is Alzheimer's disease or mild cognitive impairment.
 4. Themethod of claim 2, wherein the amyloidogenic disease is diffuse lewybody disease or Parkinson's disease.
 5. The method of claim 1, whereinthe effective dosages of at least two agents that bind to integrinsubunit αv are administered.
 6. The method of claim 1, wherein the agentis administered in combination with a secondary agent chosen from thegroup consisting of an inhibitor of Aβ production, an inhibitor of Aβdeposition, a mediator of Aβ clearance, a mediator of amyloid plaqueclearance, an inhibitor of Aβ neurotoxicity, an inhibitor of Aβaggregation, and a mediator of Aβ disaggregation.
 7. The method of claim6, wherein the inhibitor of Aβ production is a gamma secretaseinhibitor.
 8. The method of claim 6, wherein the inhibitor of Aβproduction is a beta secretase inhibitor.
 9. The method of claim 1,wherein the agent is administered in combination with an antibody to Aβ.10. The method of claim 1, wherein the agent is a peptide comprising anRGD (Arg-Gly-Asp) motif.
 11. The method of claim 1, wherein the agent isa ligand of αvβ1 integrin.
 12. The method of claim 1, wherein the agentis fibronectin or superfibronectin.
 13. The method of claim 1, whereinthe agent inhibits adhesion of αv integrin subunit-expressing cells tovitronectin or fibronectin.
 14. The method of claim 1, wherein the agentinhibits adhesion of αv integrin subunit-expressing cells toosteopontin.
 15. The method of claim 1, wherein the agent is amonoclonal or polyclonal antibody.
 16. The method of claim 1, whereinthe agent is an antibody that recognizes the same epitope as an antibodyselected from 18C7, 20A9, and 17E6.
 17. The method of claim 16, whereinthe antibody is selected from a humanized antibody, a chimeric antibody,and a nanobody.
 18. The method of claim 1, wherein the agent is anantibody selected from 18C7, 20A9, and 17E6.
 19. The method of claim 1,wherein the agent competes for binding to the integrin subunit αv withan antibody chosen from 18C7, 20A9, and 17E6.
 20. The method of claim 1,wherein the agent is a compound selected from compounds of Formula Iaand Ib

including stereoisomeric forms thereof, or mixtures of stereoisomericforms thereof, or pharmaceutically acceptable salt forms thereof,wherein: X₁ and X₃ are independently selected from nitrogen or carbon;R¹ is selected from:

wherein the above heterocycles are optionally substituted with 0-2substituents selected from the group consisting of: NH₂, halogen, NO₂,CN, CF₃, C₁-C₄ alkoxy, C₁-C₆ alkyl, and C₃-C₇ cycloalkyl; U is selectedfrom —(CH₂)_(n)—, —(CH₂)_(t)Q(CH₂)_(m) and —C(═O) (CH₂)_(n-1)—, whereinone of the methylene groups is optionally substituted with R⁷; Q isselected from 1,2-phenylene, 1,3-phenylene, 2,3-pyridinylene,3,4-pyridinylene, and 2,4-pyridinylene; R⁶ is selected from: H, C1-C4alkyl, and benzyl; R7 is selected from: C₁-C₆ alkyl, C₃-C₇ cycloalkyl,C₄-C₁₁ cycloalkylalkyl, aryl, aryl(C₁-C₆ alkyl), heteroaryl, andheteroaryl(C₁-C₆ alkyl); R¹⁰ is selected from: H, halogen, CO₂R¹⁷,CONR¹⁷R²⁰, C₁-C₆ alkyl substituted with 0-1 R¹⁵ or 0-1 R²¹, C₁-C₄ alkoxysubstituted with 0-1 R²¹, C₃-C₇ cycloalkyl substituted with 0-1 R¹⁵ or0-1 R²¹, C₄-C₁₁ cycloalkylalkyl substituted with 0-1 R¹⁵ or 0-1 R²¹, andaryl(C₁-C₆ alkyl)-substituted with 0-1 R¹⁵ or 0-2 R¹¹ or 0-1 R²¹; R¹¹ isselected from: H, halogen, CF₃, CN, NO₂, hydroxy, NR²R³, C₁-C₄ alkylsubstituted with 0-1 R²¹, C₁-C₄ alkoxy substituted with 0-1 R²¹, arylsubstituted with 0-1 R²¹, aryl(C₁-C₆ alkyl)-substituted with 0-1 R²¹,(C₁-C₄ alkoxy)carbonyl substituted with 0-1 R²¹, (C₁-C₄ alkyl)carbonylsubstituted with 0-1 R²¹, C₁-C₄ alkylsulfonyl substituted with 0-1 R²¹,and C₁-C₄ alky-laminosulfonyl substituted with 0-1 R²¹; W is—C(═O)—N(R¹³)—; X is —CH(R¹⁴)—CH(R¹⁵)—; R¹³ is selected from H and CH₃;R¹⁴ is selected from: H, C₁-C₁₀ alkyl, aryl, and heteroaryl, whereinsaid aryl or heteroaryl groups are optionally substituted with 0-3substituents selected from: C₁-C₄ alkyl, C₁-C₄ alkoxy, aryl, halo,cyano, amino, CF₃, and NO₂; R¹⁵ is selected from H and R¹⁶; Y is —COR¹⁹;R¹⁶ is selected from: —NH(R²⁰)—C(═O)—R¹⁷, —N(R²⁰)—C(═O)—R¹⁷,—N(R²⁰)—C(═O)—NH—R¹⁷, —N(R²⁰)SO₂—R¹⁷, and —N(R²⁰)SO₂—N(R²⁰)R¹⁷, R¹⁷ isselected from: C₁-C₁₀ alkyl, C₃-C₁₁ cycloalkyl, aryl(C₁-C₆ alkyl)-,(C₁-C₆ alkyl)aryl, heteroaryl (C₁-C₆ alkyl)-, (C₁-C₆ alkyl)heteroaryl,biaryl(C₁-C₆ alkyl)-, heteroaryl, or aryl, wherein said aryl orheteroaryl groups are optionally substituted with 0-3 substituentsselected from the group consisting of: C₁-C₄ alkyl, C₁-C₄ alkoxy, aryl,heteroaryl, halo, cyano, amino, CF₃, and NO₂; R¹⁹ is—O—(CH₂)_(k)N⁺(R²²)(R²³)(R²⁴)Z⁻; Z⁻ is a pharmaceutically acceptableanion selected from halide, bisulfate, sulfate, hydrogenphosphate,phosphate, toluenesulfonate, methanesulfonate, ethanesulfonate, acetate,trifluoroacetate, citrate, oxalate, succinate, and malonate; R²², R²³,and R²⁴ are independently selected from H, C₁-C₄ alkyl, and C₄-C₁₁cycloalkylalkyl; alternatively R²² and R²³ can be taken together to forma 5-7 membered heterocyclic ring system containing 1-2 heteroatomsselected from N, O and S, and R²⁴ is defined as above or R²², R²³, andR²⁴ can be taken together to form a heterobicyclic ring systemcontaining 1-2 heteroatoms selected from N, O and S; R²⁰ is selectedfrom H and CH₃; R²¹ is selected from COOH and NR⁶ ₂; k is 2; m isselected from 0 and 1; n is 1-4; and t is selected from 0 and
 1. 21. Themethod of claim 1, wherein the agent is a compound of Formula II:Formula II:

wherein R19 is chosen from —H, —CH₃, and —CH₂CH₂N⁺(CH₃)₃.
 22. The methodof claim 21, wherein R19 is —H.
 23. The method of claim 21, wherein R19is —CH₃.
 24. The method of claim 21, wherein R19 is —CH₂CH₂N⁺(CH₃)₃. 25.The method of claim 1, wherein the agent is a disintegrin.
 26. Themethod of claim 1, wherein the agent is echistatin.
 27. The method ofclaim 1, wherein the agent is a human antibody.
 28. The method of claim1, wherein the agent is a humanized antibody.
 29. The method of claim 1,wherein the agent is a chimeric antibody.
 30. The method of claim 1,wherein the agent is a nanobody.
 31. The method of claim 1, wherein theagent is an antibody fragment.
 32. The method of claim 1, wherein theagent comprises one or more heavy chains, light chains, F(ab), F(ab)₂,F(ab)_(c), or F(v) of an antibody, or any combination thereof.
 33. Themethod of claim 1, wherein the agent is an antibody and the isotype ofthe antibody is IgG1 or IgG4.
 34. The method of claim 1, wherein theagent is an antibody and the isotype of the antibody is IgG2 or IgG3.35. The method of claim 1, wherein the agent is an antibody chain. 36.The method of claim 1, wherein the agent is an antibody and the antibodycomprises two pairs of light and heavy chains.
 37. The method of claim1, wherein the agent is administered to a patient.
 38. The method ofclaim 37, wherein the agent is an antibody and the dosage of theantibody ranges from about 0.01 to about 10 mg/kg body weight of thepatient.
 39. The method of claim 37, wherein the agent is administeredwith a carrier as a pharmaceutical composition.
 40. The method of claim37, wherein the agent is administered intraperitoneally, orally,intranasally, subcutaneously, intrathecally, intramuscularly, topicallyor intravenously.
 41. The method of claim 37, wherein the patient issuffering from an amyloidogenic disease.
 42. The method of claim 41,wherein the disease is chosen from the group consisting of Alzheimer'sdisease, type II diabetes, Parkinson's disease, diffuse lewy bodydisease, amyloidosis, Down's syndrome, and a disease caused all or inpart by prion infection.
 43. The method of claim 1, wherein a nucleicacid is administered that encodes the agent.
 44. The method of claim 1,wherein the agent is chosen from the group consisting of an antisenseRNA molecule, an antisense DNA molecule, a ribozyme, RNAi, and azinc-finger protein.
 45. The method of claim 1, further comprisinginhibiting formation of an amyloid deposit.
 46. The method of claim 1,further comprising inhibiting amyloid toxicity.
 47. The method of claim1, wherein the agent does not block the maintenance phase of LTP. 48.The method of claim 1, wherein the agent suppresses amyloid-mediatedinhibition of LTP in a slice preparation in culture.
 49. The method ofclaim 1, wherein the agent suppresses inhibition of LTP by soluble Aβ.50. A method of identifying an agent that suppresses amyloid-mediatedinhibition of LTP, comprising a) identifying an agent as an integrinsubunit αv binding agent; and b) determining that the identified αvbinding agent suppresses amyloid-mediated inhibition of LTP.
 51. Themethod of claim 50, wherein the step of identifying an agent comprisesone or more of a direct binding assay, a competitive binding assay and acell adhesion assay; and wherein the step of determining that theidentified αv binding agent suppresses amyloid-mediated inhibition ofLTP comprises introducing a high frequency stimulation to a first neuralcircuit and measuring induction of LTP, introducing a high frequencystimulation to a second neural circuit in the presence of Aβ andmeasuring an inhibition of LTP induction, and introducing a highfrequency stimulation to a third neural circuit in the presence of Aβand the agent, and measuring a suppression of inhibition of LTPinduction.
 52. An agent that suppresses amyloid-mediated inhibition ofLTP, identified by the method of claim
 50. 53. The agent of claim 52,wherein the agent is an antibody.
 54. A composition comprising the agentof claim 52 and a pharmaceutically acceptable carrier.
 55. A method ofsuppressing amyloid-mediated inhibition of long-term potentiation (LTP),comprising administering an effective dosage of an agent identified bythe method of claim
 50. 56. An agent that suppresses amyloid-mediatedinhibition of LTP, identified by the method of claim
 51. 57. The agentof claim 56, wherein the agent is an antibody.
 58. A compositioncomprising the agent of claim 56 and a pharmaceutically acceptablecarrier.
 59. A method of suppressing amyloid-mediated inhibition oflong-term potentiation (LTP), comprising administering an effectivedosage of an agent identified by the method of claim
 51. 60. A method oftreating an amyloidogenic disease characterized by Aβ deposition,comprising administering an αv antagonist or an inhibitor of αv-mediatedcell adhesion in an amount effective to suppress amyloid-mediatedinhibition of long-term potentiation (LTP).
 61. The method of claim 60,wherein the amyloidogenic disease is Azheimer's disease.
 62. The methodof claim 60, wherein the amyloidgenic disease is mild cognitiveimpairment.